Affects children under age 5; mass immunization campaigns have reduced
polio cases by > 99%. To get polio-free status, any area or country should
not have a case for 3 consecutive years
USA : by one estimate, polio paralyzed 254,000 Americans, many of them
children. Vaccination gradually eliminated U.S. outbreaks. In 1960, there
were 2525 paralytic polio cases in the country, but by 1965, the number
had dropped to 61. The last case of infection with the wild poliovirus
was reported in 1979. The USA stopped using polio vaccines that contain
weakened strains of the live virus in 2000. Before use of the live oral
poliovirus vaccine (OPV)
was discontinued, it caused about 8 cases of vaccine associated paralytic
poliomyelitis (VAPP) a year in the U.S., on average. The last outbreak
associated with wild poliovirus in the USA was among a religious group
(Amish) that does not accept vaccinations due to religious beliefs. The
"itinerary" of the wild poliovirus involved in that outbreak probably began
in Kuwait, as the virus identified was genetically similar to a strain
of poliovirus that was in circulation in Kuwait in 1977. It then went to
the Netherlands, where it circulated among a religious group that shunned
vaccinations (and still shuns vaccines today), in which there were approximately
80 cases; it then traveled to Canada and circulated among Canadian members
of this same religious group, resulting in 11 cases, and then traveled
to a different religious group in the USA and resulted in 15 casesref5,
ref6,
ref7.
A vaccine-derived type 1 strain was isolated in a Minnesota 7 months girl
suffering from SCID on September 29, 2005 (1st case of polio reported in
the state since 2000) in an Amish community whose members predominantly
were unvaccinated for polio. The patient has no paralysis; the source of
the patient's infection is unknown. An estimated 93% of Minnesota's population
has had the full primary series of 3 polio shots, and 98% of Minnesota
children have been immunized by the time they start school. In 1946, the
Minnesota State Fair was canceled, as state health officials were recording
as many as 50 new cases a day. OPV has been associated with rare cases
of vaccine associated paralytic poliomyelitis (VAPP) in individuals
who have directly received the vaccine and in those who have had contact
with recently vaccinated individuals. In addition, there have been reports
of cases of paralytic poliomyelitis associated with circulating vaccine
derived polioviruses (cVDPV) where there has been a reversion to neurovirulence
of the involved circulating vaccine derived virus. With respect to the
former situation (VAPPs), during the period 1980-1994, of 133 confirmed
cases of paralytic poliomyelitis reported in the USA, 125 (94%) were associated
with administration of OPV (annual mean: 8 VAPP cases) (6 were imported
cases and 2 were indeterminate without a poliovirus isolation, and no history
of direct or indirect contact with the OPV). Of the 125 VAPP cases, 49
(39%) were among immunologically normal recipients of OPV, 46 (37%) among
immunologically normal contacts of OPV recipients (including 6 cases among
persons from whom vaccine-like poliovirus was isolated but who had no history
of direct contact with vaccinees), and 30 (24%) among immunologically compromised
OPV recipients or contacts of OPV recipientsref.
Since the USA changed vaccination policy to use IPV rather than OPV, there
have been no further cases of VAPP reported in the USA. Information that
would be of interest is the age of the involved case, and possible contacts
with known recent OPV recipients, either through travel of this case to
countries where OPV is currently used or through known contact with recent
OPV recipients visiting from countries where OPV is used. Other information
on the investigation that is of interest is environmental sampling of sewage
in the geographical area where the case originated to know whether there
is evidence of cVDPV in the general area. There are concerns about chronic
infection of an immune-compromised host with resultant neurovirulence reversion
of the virus and potential spread of VDPV in the communityref1,
ref2,
ref3,
ref4.
3 additional children -- all members of another Amish family within the
index patient's community -- with polio virus infection were identified
in central Minnesota. The identification of 4 infections (involving 2 families
that seem to have had contact with each other) suggests that there has
been at least 2 and possibly 3 generations of passage of this vaccine poliovirus
(the 1st generation being the original vaccinated individual -- the "index
infection", the 2nd the immunocompromised infant identified on 1 Oct 2005,
and now the 3 children in a contact family, although they may have been
infected at the same time as the infant with a common exposure to the "index"
infection). However, the news release does not mention identification of
the "index" infected individual as yet, somewhat suggesting that there
is cVDPV in the above community. Somewhat ironic, since that very same
trait of the vaccine (OPV) -- spread to other non-vaccinated individuals
-- is a positive trait in countries where wild poliovirus is circulating,
as it helps to increase the overall "vaccination coverage" by spreading
the vaccine virus in the community and infecting (and thereby protecting)
other children who had not received the vaccine. The above 4 "cases" mentioned
are not cases of VAPP, as there is no paralytic disease associated with
these infections. One of the serious concerns in the current incident
is the possibility of reversion of neurovirulence of the vaccine virus
after continued passage in polio-naive individuals (with no pre-existing
immunity, either through adequate vaccination or through prior exposure
to poliovirus), especially in the immunocompromised infant mentioned as
the 1st case, as chronic infection with vaccine-derived poliovirus has
been reported in immunocompromised hosts. if one has been adequately vaccinated,
the risk of paralytic disease from contact with a cVDPV is very low, and
with a 93% vaccination coverage rate with IPV in Minnesota, unless the
virus enters a pocket of susceptibles, the risk of further cases associated
with this event is low. That being said, it appears as though the virus
has entered a pocket of susceptibles (a community that rejects vaccination
based on religious grounds), and the possibility of spread to other similar
religious communities in the USA is a real concern. We do not know the
actual risk of paralytic disease from cVDPV, but we do know it has occurred
(in Haiti and the Dominican Republic, Madagascar, the Philippines and Egypt)ref1,
ref2,
ref3.
The findings in this report are the 1st identification of a VDPV in the
USA and the 1st occurrence of VDPV transmission in a community since OPV
vaccinations were discontinued in 2000ref1,
ref2,
ref3.
The extent of circulation within the affected community is not yet known.
However, the identification of poliovirus infection in the index patient
and 3 other unvaccinated children in a community at high risk for poliovirus
transmission raises concerns regarding 1) transmission to other communities
with low levels of vaccination and 2) the risk for a polio outbreak occurring
in the United States. Potential also exists for transmission of this virus
to other immunodeficient persons. Although this VDPV has not been associated
with paralytic disease,
based on previous experience with VDPVs, the virus is considered to
have potential both for wider transmission and for causing paralytic disease.
VDPVs emerge from OPV viruses as a result of 1) their continuous replication
in immunodeficient persons (immunodeficiency-associated or iVDPVs)
such as the index patient in this investigation or 2) their circulation
in populations with low vaccination coverage (circulating or cVDPVs)ref.
During community circulation, cVDPVs often recombine with other species
C enteroviruses, which is not characteristic for iVDPVsref.
Because polioviruses accumulate nucleotide changes at a constant rate of
mutation (about 1% per year), the time of replication can be inferred from
the degree of divergenceref.
Because cVDPVs commonly revert to a wild poliovirus phenotype, they can
have increased transmissibility and high risk for paralytic disease; cVDPVs
have caused outbreaks of poliomyelitis in several countries (1). VDPVs
in highly immunized populations are rare. Before the VDPV identification
in Minnesota, the most recent known VDPV excreter in the USA was a child
with SCID (now deceased) who developed vaccine-associated paralytic poliomyelitis
in 1995ref.
Given the degree of difference (2.3%) from the parent Sabin poliovirus
type 1 strain, the virus isolated from the index patient is estimated to
have been replicating for about 2 years, which means the virus likely is
older than the infant. OPV is still widely used in most countries; however,
because OPV has not been used in the United States since 2000 and in Canada
since 1997, the original source of this virus likely was a person who received
OPV in another country. Neither the infant nor her family members had any
history of international travel. This virus is not related to other known
iVDPVs or to any type 1 cVDPVs that caused outbreaks such as those in Hispaniola
during 2000-2001, the Philippines during 2001ref,
or Indonesia during 2005. Most poliovirus infections are asymptomatic or
cause mild, febrile disease. Poliovirus infections occasionally cause aseptic
meningitis, and one out of 200 infections from poliovirus type 1 results
in paralytic poliomyelitis, characterized by acute onset of flaccid paralysis
that is typically asymmetric and associated with a prodromal fever. Poliovirus
is spread through fecal material, oral secretions, and fomites. Widespread
transmission among vaccinated health-care workers or in a community with
high vaccination coverage is unlikely because fully vaccinated persons
are not at risk for disease from this or other polioviruses and seldom
shed the virus for longer than a week if they are infected. The National
Immunization Survey reports that polio vaccination coverage in Minnesota
is 93% for children aged 19-35 months and 98 per cent for school-aged children;
however, communities of unvaccinated persons exist in Minnesota and many
other statesref.
The risk for transmission in communities with low vaccination coverage
is high. The estimated rate of transmission for wild poliovirus among unvaccinated
household contacts is 73-96% (Zimmerman K, Middleton D, Burns I, Clover
R. Routine vaccines across the life span, 2003 clinical review. J Fam Pract
2003; 52(suppl 1): s1-s21). Contacts between persons in communities with
low vaccination coverage pose the potential for transmission of this poliovirus
to other communities in the United States, Canada, and other countries.
The last wild poliovirus outbreak in the USA occurred in 1979 and was caused
by a wild type 1 poliovirus. In that outbreak, 10 paralytic poliomyelitis
cases and 4 other poliovirus infections occurred among unvaccinated Amish
persons and members of other religious communities with low levels of vaccination
who lived in Iowa, Missouri, Pennsylvania, and Wisconsin. The source of
this outbreak was traced to religious groups in Canada and the Netherlands
that also had low levels of vaccinationref.
A polio outbreak in 1993 in the Netherlands with 71 paralytic cases among
members of unvaccinated religious communities also resulted in poliovirus
transmission without paralytic disease in Alberta, Canada; no evidence
of transmission from this outbreak was found in the USAref.
Persons in communities with low vaccination coverage should be warned of
the potential risk for poliomyelitis. States with large communities with
low vaccination coverage should identify these communities, assess their
current vaccination status, and offer IPV. These states also should establish
enhanced or active surveillance for AFP, GBS, and transverse myelitis.
Physicians should be aware of and vigilant for poliomyelitis and other
causes of AFP in patients. Stool samples, throat swabs, cerebrospinal fluid,
and serum should be collected for viral culture and serology from these
patients. With evidence of transmission in Minnesota, serologic and/or
stool surveys to detect poliovirus type 1 circulation in affiliated communities
with low levels of vaccination also should be considered. IPV, the polio
vaccine currently used in the United States, provides immunity against
this vaccine-derived poliovirus strain. The Advisory Committee on Immunization
Practices (ACIP) recommends that a full 3-dose IPV series be administered
on an accelerated schedule if polio immunization status is unknown or not
documentedref.
A booster dose of IPV is recommended for adults in susceptible communities
and health care workers at high risk for exposure who have completed a
primary series but have not received an adult booster dose.
1988 : 350,000 cases in > 125 countries
2001 : 483 cases
2002 : 1,919 cases in 7 countries (Afghanistan, Egypt, India, Niger, Nigeria,
Pakistan, and Somalia)
2003 : 784 cases in 6 countries (Afghanistan, Egypt, India, Niger, Nigeria,
and Pakistan : eradicated in Somalia)ref1,
ref2,
ref3,
ref4,
ref5.
> 75% were concentrated within 5 hotspots in just 3 countries : India,
Nigeria (the most populous country of the African continent (2003 population
projected from 1991 census report: 125 million), reported 355 wild poliovirus
(WPV) cases, virtually all of them in the north of the country, accounting
for 45% of cases reported globally and >80% of cases reported from the
African Region (AFR)). During January 2003--March 2004, importations
of WPV occurred in 8 countries that were previously polio-free: 5 in
the West African block (Benin, Burkina Faso, Cote d'Ivoire, Ghana, and
Togo) and 3 in the Central African block (Cameroon, Central African Republic,
and Chad), resulting in 63 polio cases
2004 : Asian and North African regions have less polio than ever, and are
on track for disease-free status by December 2004 : together, Afghanistan,
Egypt, India (including an infant from a slum in Dindoshi, Malad east,
Mumbai) and Pakistan reported just 21 cases in the period January-May 2004,
compared with 94 this time in 2003. But 5 times as many children in west
and central Africa have been paralyzed by polio so far in 2004 compared
to the same period in 2003. By 23 Jun 2004, 257 children have been paralyzed
in Nigeria (48 of the world's 72 reported infections, or 2/3, at Apr 7),
following the suspension of polio immunization campaigns in northern Nigeria
late last year : the cases probably represent about 1% of actual infections
in those areas : in March 2004, Nigeria saw the "highest ever-recorded"
monthly incidence of wild polio virus, with 85 confirmed cases across the
country.
As of April 2004, only 6 of the 36 states in Africa's most populous country
-- the mainly-Christian southern states of Abia, Adamawa, Ebonyi, Edo,
and Rivers, and the central state of Nasarawa -- were polio-free, warning
of worse to come as Nigeria's annual rains intensify (Nigeria's rains begin
in March and build up in August and September), when children get contact
with contaminated water and food. 11 countries in Africa have had poliomyelitis
cases confirmed -- Benin, Botswana, Burkina Faso, Cameroon, Central African
Republic, Chad, Cote d'Ivoire, Ghana, Niger, Nigeria and Sudan (a country
which had not seen the disease in more than 3 years). Only Niger and Nigeria
were considered to be polio-endemic at the beginning of 2003, where transmission
of the wild poliovirus had not as yet been interrupted. In the remaining
9 countries, wild poliovirus isolates have been identified and found to
be similar to those circulating in Nigeria -- circumstantial evidence that
the ongoing poliovirus transmission in Nigeria continues to seed other
African countries where poliovirus transmission had been interrupted. In
some instances, the cases and families were shown to have direct contact
with Nigeria either through personal travel or contact with travellers
from Nigeria. In the case of Botswana, a direct link had not been established,
but the wild poliovirus identified was similar to those currently circulating
in Nigeria. The child paralyzed on 20 May 2004 in Darfur, Sudan, an area
with significant infrastructural compromise as a result of civil unrest,
does not presently report a direct contact with Nigeria, yet the virus
isolated is also similar to those currently circulating in Nigeria. Kano
State in Northern Nigeria continues to be the epicenter of this polio epidemic,
and until full-scale resumption of vaccination activities in that area,
the likelihood of more importations of the wild poliovirus into countries
with previously interrupted transmission remains high. Today, however,
Africa accounts for nearly 90% of the global polio burden, with children
now paralyzed in 10 previously polio-free countries across the continent.
Epidemiologists fear that a major epidemic this autumn (during the polio
'high season') would leave thousands of African children paralyzed for
life. In response to this threat, they recommended plans to hold massive,
synchronized immunization campaigns across 22 African countries in October
and November 2004, aiming to reach 74 million children. Polio has re-emerged
in
Guinea (date of paralysis: 5 June 2004; previous last polio case:
27 October 1999)
Mali (dates of paralysis: 15 May and 5 July 2004; previous last
polio case: 12 January 1999), countries that had previously freed themselves
of the disease : the virus spread from Nigeria, one of the last strongholds
of the disease.
Vaccinations in Nigeria's Kano state resumed just a short time ago, on
31 July. The new cases mean there are now 12 formerly polio-free countries
that have been re-infected with virus since January 2003. Guinea and
Mali are home to 1 and 2 new cases respectively. 3 new cases of polio paralysis
have also been confirmed in Sudan's conflict-stricken Darfur region (dates
of onset of paralysis :7 Jul, 11 Jul, and 17 Jul). Guinea and Mali are
outside a ring of African countries that performed coordinated immunization
campaigns in February and March 2004 to try to halt the spread of polio
from Nigeria and Niger. Further synchronized vaccinations are planned in
22 countries, including Nigeria and Niger, in October and November 2004.
Health professionals aim to immunize 74 million children under the age
of 5. Although similar campaigns in 2000 and 2001 stopped polio transmission
in most of these countries, civil unrest in Côte d'Ivoire and Darfur
will make it hard to reach every child this year. The Global Polio Eradication
Initiative warned, however, that preparations for these activities, and
additional, synchronized rounds in 2005, are being seriously compromised
by an ongoing funding gap of USD 100 million. The sobering statistic is
that the cost of responding to the importations in 2003 was USD 25 million,
half of the 50 million projected to meet 2004 vaccination goals.
This process will be repeated in 2005, at the cost of another USD 50 million.
Sudan : the number of confirmed cases of polio has made a dramatic
rebound in a country that had been declared polio-free in 2001. The tiny,
sand-blown Arab village of Hara al-Zawiyah, in a remote corner of Darfur,
appears to be spared the violence and suffering endemic to the rest of
western Sudan. But even here, people are increasingly fearful of the diseases
taking hold after 2 years of civil war. Polio has surged to the top of
their list of concerns, after a child in the town of Kass, < 90 miles
to the south, was paralyzed by it 6 months ago. Since then the number of
confirmed cases of polio-induced paralysis in Sudan has soared to 54. Sudan
is having a major polio outbreak, particularly in Port Sudan, a Red Sea
ferry port. Because paralysis of limbs occurs in only 1 in 200 cases, health
experts say there is a high probability that > 10,000 Sudanese have been
infected with the virus, prompting several U.N. aid agencies to issue repeated
warnings that Sudan is in the midst of a massive outbreak. Particularly
disturbing for health workers is the virus's potential for spreading in
the crowded, festering camps of western Sudan and neighboring Chad, where
nearly 2 million people have sought refuge in the wake of atrocities by
pro-government Arab militias aiming to crush a rebel uprising. In much
of Darfur, ongoing attacks by militias and rebel fighters have forced U.N.
agencies and non-governmental aid groups to evacuate their workers, halting
the distribution of food and medicine to hundreds of thousands of people
left homeless by the conflict. There are 3 factors that make the situation
in Sudan particularly alarming :1st of all, it's the largest country in
Africa in terms of land mass, and borders 9 other countries. So there are
porous borders with 9 countries across which this virus could now spread.
Particular concern of course is that, from the Sudan, it could get into
the Middle East or, with the borders with the Congo, it could re-infect
that country. And any of these developments would make the global eradication
much, much higher risk, much, much more difficult, and much, much more
expensive. Secondly, there's the internal situation in the country where
there's civil unrest or disturbances in 2 large areas of the country, which
really could allow the continued propagation of the virus within the country.
And then, finally, the Sudan, being both an Arab and an African country,
in many ways has got important international links which could lead to
the further dissemination of the virus and even the re-infection of the
Middle East. About 2400 health workers have fanned out across Darfur to
administer the vaccine to nearly 2 million children < 5 years old. 79
new cases had been recorded across the country : 32 of the reported cases
were found in the state of Khartoum, while Unity state and Western Upper
Nile in the south each reported 5 cases. Initial testing indicated that
both the genetic P-1 strain, related to reported cases in Nigeria, and
the unrelated P-3 strain were present in Sudan, suggesting that the outbreak
might have resulted from both imported and locally transmitted cases. In
the most recent Polio Lab Network Quarterly report available (Sep 2004)
at the WHO vaccines website there is mention that the type 1 poliovirus
identified earlier in the year in the Sudan was genetically linked to viruses
in Chad (which in turn were linked to the ongoing outbreak in Nigeria)ref.
Sudan belongs to the Eastern Mediterranean Region (EMR) of WHO, where as
of the Sep 2004 lab report there had been 6 identifications of wild poliovirus
type 3 in 2004. An interpretation of the identification of wild poliovirus
type 3 in some of the cases is that there has most likely been continued
circulation of type 3 poliovirus in the country, in the absence of detection
of clinical cases, prior to this current outbreak. This raises a concern
that the level of surveillance for cases of acute flaccid paralysis (AFP)
may have been suboptimal during the interval (3 years) during which there
was apparent interruption of transmission of the wild poliovirus circulation
in the country -- perhaps not unrelated to the civil unrest in the country
impeding health initiatives. The northern Nigerian state of Kano reported
nearly 700 confirmed cases, 7 times the number of cases reported by India,
the world's 2nd most polio-prone country. In addition to the problems in
Sudan, the campaign to eradicate polio has hit another snag: a USD 200
million budget shortfall, as some countries have yet to deliver promised
funding to the program. The shortfall has led some U.N. officials to consider
postponing or reducing immunization programs in Africa and Asiaref.
Prior to this outbreak, transmission of wild poliovirus had been interrupted
in April 2001, leaving an interval of just over 3 years without reports
of cases. Of note, the most recent confirmed case count from the Sudan,
available on the polio eradication website is 47 casesref,
7 less than reported in the above newswire. A current polio outbreak in
the Sudan, caused by an imported type 1 poliovirus, continues to escalate.
125 cases have now been confirmed from 17 of the country's 26 states (as
of 6 Jan 2005), since the 1st case was identified in Darfur in May 2004.
The Sudan is continuing its intensification of polio immunization campaigns,
with support from WHO, UNICEF and other polio partners. Following 4 mass
immunization campaigns in the Darfur region between July and November 2004,
and 2 nationwide campaigns in October and November 2004, planning is currently
under way for the next rounds of nationwide immunization campaigns commencing
on 10 Jan, 25 Feb and late March 2005.
Saudi Arabia (polio-free since 1995) : a 2-year-old Sudanese
girl from Dar Elneeem district, Port Sudan, experienced onset of paralysis
on 6 Nov 2004, 1 day after arriving in the port city of Jeddah with her
family. As the date of onset of symptoms was 1 day following entry into
the country, one hopes that there wasn't extensive contact with other individuals
in the country to establish local circulation of the wild virus. According
to the available information on polio vaccination coverage from WHO/UNICEF
estimates, coverage with 3 or more doses of polio vaccine in Saudi Arabia
has been above 90% since 1989, with coverage > 95% since 2000 (most recent
figure, 95% in 2003)ref.
These coverages should theoretically be high enough to prevent widespread
poliovirus circulation in the country. Concerns are more that there might
be contact with other migrant populations, among whom polio vaccination
coverage may not be as high as those in Saudi Arabia. Although genetic
data on the virus isolated from the case in Saudi Arabia are not yet available,
almost all other viruses identified in 2004 in the Sudan are closely genetically
related to polioviruses originating in northern Nigeria and Chad. The escalating
outbreak in the Sudan and the polio case in Saudi Arabia further underline
the high risk posed to polio-free areas by the continuing epidemic in west
and central Africa. This risk is compounded by the growing vulnerability
of populations to polio globally, following the cessation of preventive
polio immunization campaigns in many polio-free countries in 2002-2003.
Children globally will continue to be at risk of polio from such importations
until the disease is eradicated everywhere. The Government of Saudi Arabia
is also implementing an emergency response to the importation, including
heightened disease surveillance throughout the country, to ensure that
any transmission of wild poliovirus in Saudi Arabia is identified and stopped
rapidly. WHO notified countries neighbouring the Sudan of the high risk
for further importations, and urged a strengthening of surveillance for
polio, high routine immunization coverage of infants, and, if appropriate,
supplementary polio immunization campaigns. The 2nd, more worrisome case
was discovered in a 5-year-old Nigerian boy who developed paralysis
on 15 Dec 2004. What made it more troubling was that his family had lived
for several years in an illegal encampment on the outskirts of Mecca, so
he must have caught it in Saudi Arabia. Polio apparently reached Mecca,
Islam's holy city, just before last month's annual pilgrimage by 2 million
Muslims, and WHO officials now fear that it could be spreading around the
world, carried by returning pilgrims. In crowded nations with spotty vaccination
coverage, like Bangladesh and Indonesia, there could be substantial consequences.
The Saudis started a sweeping polio inoculation campaign in September 2004,
hoping to head off the threat before the height of the hajj, or pilgrimage,
in late January 2005. Spotting new outbreaks in far-flung countries will
still take weeks. Paralysis affects only about 1 in 200 carriers of the
virus, symptoms can take up to 35 days to emerge, pilgrims traveling by
bus or boat can take weeks to get home, and epidemiological reporting in
poor countries is often slipshod. The virus lives in the intestine and
spreads through fecal-oral contact, so anything from changing a diaper
to sharing a food dish or swimming in contaminated water can transmit it.
Polio vaccination was not required for hajj pilgrims because it was a rapidly
diminishing threat until this year. Even if it was required, thousands
of pilgrims arrive illegally, and many legal visitors carry forged immunization
records. Polio has been spreading from northern Nigeria since 2003, when
vaccination campaigns there were halted for months after Muslim imams and
local politicians spread rumors that the vaccine could make women sterile,
transmit AIDS or was made with pork products. Most cases related to that
outbreak have been in the largely Muslim Sahel, the band of arid but arable
land south of the Sahara Desert stretching from Mali to Ethiopia. The remaining
pockets elsewhere are also mostly in Muslim areas: Pakistan, northern India,
Afghanistan and Egypt. In September 2004, Saudi Arabia began vaccinating
800 000 people in Mecca and in the Jeddah area, where pilgrims disembark.
Each case of paralysis implies that many more virus-carriers are nearby.
Most victims suffer symptoms no more serious than those of flu, but even
people with no symptoms can pass the virus. In 1988, when polio was endemic
in 125 countries, the annual assembly of the health ministers of all nations
in Geneva declared their intent to eradicate it by the year 2000. That
target was missed, but USD $3 billion in vaccination campaigns drove the
disease back until it existed in only 6 countries by the end of 2003: Nigeria,
India, Pakistan, Niger, Egypt and Afghanistan. But in 2002, Muslims in
large swaths of Nigeria and Niger began resisting vaccination. The reasons
were complex: religious and political rivalries, a failed drug trial, and
reports of the controversial 1999 book "The River," which linked
AIDS to polio vaccinations in the Congo in the 1950's. It took until last
year to persuade the governor of Nigeria's Kano State, one of the loudest
critics of the vaccine, to accept it as long as it was imported from a
Muslim country. He inaugurated a new vaccination drive in October 2004
by allowing Nigeria's president, Olusegun Obasanjo, to give his daughter
drops of a vaccine made in Indonesia. But by that time, the virus had escaped.
Last year, paralysis cases appeared as far west as Mali and as far south
as Botswana. Genetic testing identified them as a strain from Nigeria.
The most persistent migration was to the east, with cases spreading along
the Sahel's highways. Sudan, which had been polio-free for 3 years, found
a case imported from Chad in May 2004, and by late January 2005 had 112
cases, most of them in Darfur, on the Chad border, around the capital,
Khartoum, and in the state bordering the Red Sea. Some Sudanese officials
suggested that it had been spread by refugees fleeing fighting in southern
Sudan, and a polio expert at the Centers for Disease Control and Prevention
in Atlanta recently offered that explanation. But Dr. Aylward said it "didn't
make any sense" because the Khartoum refugee camps had existed for years
and cases were exploding in Port Sudan, the jumping off point for Mecca.
Tens of thousands of pilgrims pile up in Port Sudan, and they can be there
for weeks or months. Another urgent worry of his, he said, was that the
hundreds of truckers from landlocked Ethiopia who use Port Sudan could
carry polio back home, where immunization rates are low. Mr. Al-Jubeir
said Saudi Arabia hires thousands of extra doctors for the hajj season,
who watch for signs of disease among the millions entering through special
airport and boat terminals set aside for pilgrims. However, he said, they
cannot spot someone with no symptoms, and many people carry vaccination
records that were stamped in return for bribes in their home countries.
Also, the Saudi border police have caught as many as 52 000 people a month
sneaking into the country, mostly from Africa, through Yemen. During the
hajj, vast crowds circle the Grand Mosque and stone the pillars of Satan
while pressed so closely together that, in some years, many have died in
the crush. Hundreds of thousands live in government-inspected tent cities,
but thousands camp illegally in the mountains around Mecca with no health
or sanitation facilities. The 2000 hajj saw a serious outbreak of meningococcal
meningitis. Now, pilgrims are supposed to show proof of vaccination against
it before they board planes at home, and those from countries where meningitis
is common are required to swallow an antibiotic upon arrival. This year
the Saudis required those vaccinations and, for pilgrims from certain countries,
yellow fever. Most Muslims who fly to Saudi Arabia each year do not normally
bring their children, since the hajj is an obligation ofadults and involves
long treks under the desert sun. But pilgrims from Africa too poor to fly
may have no choice. The above article is very complete in its discussion
on the possible implications of poliovirus circulation in Mecca during
the time of the haj. As mentioned above, there was an outbreak of
meningococcal meningitis W135 that occurred during the haj with multiple
importations to countries of origin of haj attendees. The concern above
is that there was presumptive evidence of circulation of the wild poliovirus
in Saudi Arabia as the 2nd reported case did not have a history of travel
preceding the onset of illness and therefore was infected in Saudi Arabia.
We do not know if there was direct contact with travellers from known endemic
areas. We await further information on the investigation of this case as
well as possible additional cases that may have been related to contact
with returnees from the haj. Young pilgrims coming from 15 from the 19
countries currently reporting polio cases (Afghanistan, Angola, Burkina
Faso, Cameroon, Central African Republic, Chad, Ivory Coast, Egypt, Eritrea,
Ethiopia, Guinea, India, Indonesia, Mali, Niger, Nigeria, Pakistan, Sudan
and Yemen) for the high Umrah season of Ramadan in October 2005 and the
Haj in January 2006 will have to prove that they have been immunized against
the crippling virus
Cote d'Ivoire (polio-free since 2001) : the number of recorded cases
of
polio shot up to 17 in 2004 from just 1 the previous year, and the real
situation on the ground may be worse given that access to the rebel-held
north of the country is difficult. Instability in the West African country,
which has been partitioned into a government-run south and a rebel-held
north since a failed coup > 2 years ago, was the main reason behind the
disruption of vaccination campaigns. The most recent flare-up in the long-running
conflict in early November forced the Health Ministry to postpone 2 rounds
of a national polio immunisation campaign for 5.1 million children planned
for November and December. 15 of the 17 cases reported during 2004 were
in the government-run south, but he added that the situation in rebel territory
was probably bleaker than the statistics suggested. In its 2004 annual
report, UNICEF sounded the alarm that health care in the north was in tatters,
with few doctors and nurses and virtually no routine vaccinations. Cote
d'Ivoire is really of great concern because the cases aren't concentrated
in one area. So the threat to children is not localised, it's nationwide.
Cote d'Ivoire borders 5 countries and populations in the region are mobile,
providing fertile conditions for the polio virus to spread. Cote d'Ivoire
is the economic magnet for the sub-region. Children are travelling back
and forth with their families, so the regional aspect of the campaign is
crucial
Ethiopia (polio-free since 2001) : a 2-year old girl was diagnosed
with polio in December 2004. The discovery makes Ethiopia the 14th country
to experience a resurgence of the disease since polio began to spread from
northern Nigeria in mid-2003 after several provinces suspended vaccination.
The WHO and the UNICEF announced the Ethiopian case on Thursday 24 Feb
2005 as authorities prepared for an immunization drive in 22 African countries
beginning on Sat 26 that aims to inoculate 100 million children under age
5 (countries joining the campaigns this round include the Democratic Republic
of Congo, Ethiopia, and Eritrea on the southern and eastern edges of the
epidemic). The number of reported polio cases in Ethiopia rose sharply
from 2 to 16 as of 30 Aug 2005 with most recent date of onset 16
Jul 2005. The first 2 cases were children living close to the border with
Sudan, where a polio outbreak was reported in December 2004. Both cases
were wild polio virus type 1 and genetically linked to the polio virus
circulating in neighbouring Sudan. The additional 14 cases were detected
in children aged between 8 months and 11 years in Tigray, Amhara and Oromiya
regions of Ethiopia. When the first cases were reported, the UN made an
urgent appeal for USD 4.9 million to vaccinate 14.7 million children against
polio. The Ethiopian government declared a public health emergency and
launched 2 rounds of nationwide polio immunisation campaigns in April and
May 2005. A 3rd campaign was completed in August 2005. Ethiopia was expecting
to be declared polio-free in 2005 -- a qualification it would have achieved
after recording no cases for 3 years. Polio activity in Ethiopia is being
considered as due to importation and not as yet due to re-established transmission
(the latter being considered once there are > 6 months of documented wild
poliovirus transmission in a country following importation). The number
of previously polio-free countries with polio outbreaks related to the
outbreak in Northern Nigeria in 2003 continues to grow (presently 14, including
Yemen, Ethiopia, Sudan, Chad, Mali, Eritrea, Cameroon, Saudi Arabia, Guinea,
Central African Republic, Burkina Faso, Cote D'Ivoire, Benin, & Togo).
Prior to the importation of wild polio virus into Ethiopia in 2004, the
last case (a wild type 1 poliovirus) was reported in a child from the then
KAT zone of Southern Nations Nationalities Peoples Region in January 2001.
Yemen (polio-free since disease surveillance began in 1996) : a
cluster of acute flaccid paralysis (AFP) occurred in 4 children aged 18
months to 7 years in the Yemeni Red Sea port city of al-Hudaydah, Hudeida
governorate, which first showed signs of paralysis in February or early
March 2005. All of the children had been vaccinated, but apparently not
enough times. In countries with hot weather, open sewers and many other
intestinal viruses, it can take 6 to 8 doses of vaccine to produce the
same immunity that 3 or 4 do in cooler, cleaner countries. Only about 1
case in 200 leads to paralysis, so there could be at least 800 more carriers
in Yemen. On 20 Apr, results of testing of stool specimens of 4 of the
cases by the polio network laboratory in Oman revealed wild poliovirus
type 1. Health officials are searching for other cases in the Arab state
as scientists at Centers for Disease Control and Prevention in Atlanta
examine the genetic composition of the virus to see whether it is indigenous
and signals a new outbreak or stems from another country. There's as much
traffic into Yemen from Sudan as there is from Saudi Arabia, so it's just
as likely it came from there. Yemen is the 15th previously polio-free country,
including 13 in Africa, to report an outbreak since northern Nigeria suspended
vaccinations in late 2003 for 10 months, sparking an epidemic that has
spread across Africa. The WHO needed $50 million in additional funding
before June 2005 if it was to succeed in wiping out the virus by the end
of 2005. An additional USD 200 million is needed for 2006 activities. Yemen
has already conducted a nationwide immunization campaign on 13-15 Apr 2005
(its first such drive since 2001), to immunize all of the country's 4.5
million children under the age of 5 years after a surge of new cases in
Saudi Arabia, Sudan, and Ethiopia made precautions necessary. WHO is working
with the Ministry of Health in Yemen to plan for further intensive house-to-house
immunization activities in the immediate geographic vicinity of the cases.
Planning for the next nationwide immunization campaign to be conducted
between 30 May and 2 Jun 2005 is being intensified. Contingency plans for
a potential 3rd campaign since 11 Jul 2005 are being discussed. 2
supplementary immunization activity (SIA) in Yemen will cost over USD 2
million; at the same time, the agency's USD 25 million polio emergency
fund has been depleted of all but USD 500,000 because of efforts in Sudan
and Ethiopia. Many citizens work in wealthy Persian Gulf states, many Sudanese
teach in Yemeni schools, and African traders move through on their way
to the gulf. Earlier in 2005 tens of thousands of people enter Saudi Arabia
illegally each month through Yemen : the bleak desert they share is named
the Empty Quarter and the border is officially undefined. Usually we're
able to knock it out quickly, like we did in Botswana in 2004, or in 2003
when we had an import from India into Lebanon, or in 2001 when we had cases
in Georgia and Bulgaria, but we've exhausted our emergency reserve. So
the great news is that cases are plummeting in Nigeria and Niger and India
(14) and Pakistan (6). But our ability to respond to these sparks in dry
tinder is way, way downref.
Experts are now planning an outbreak response, using the recently-developed
monovalent
oral polio vaccine type 1 (mOPV1) : 6 million doses have been shipped
to Yemen. Compared to the commonly-used trivalent OPV, which offers protection
against all 3 types of wild poliovirus, mOPV1 provides a greater immunity
to type 1 wild poliovirus with fewer dosesref.
A recent newswire provided an unofficial report of 36 additional suspected
cases of polio in Yemen, but not as yet with laboratory confirmation. No
cases caused by indigenous WPV type 2 have been reported in the world since
September 1999. Epidemiologic and virologic evidence suggest that WPV type
3 might no longer circulate in Egypt and, since the second half of 2004,
in most areas in northern India where polio is endemic. Because of
the probable absence of WPV type 3, monovalent oral polio vaccine type
1 (mOPV1) will be used as an additional tool to interrupt the last chains
of WPV type 1 transmission in these countries. This vaccine elicits a higher
population immune response per dose against WPV type 1 than the trivalent
OPV and will be used in high-transmission areas of India during April-May
2005 and nationwide in Egypt in May and in selected SIAs in the future.
During 2004, laboratory-based surveillance in several countries identified
the circulation of WPV type 1 and WPV type 3 where cases have not been
reported. In Egypt, only one WPV type 1 confirmed case of polio was reported
in 2004; however, sampling of sewage indicates persistent, low-level transmission
of 2 separate lineages of WPV type 1 across the country, particularly in
Cairo/Giza (lower Egypt) and Minya and Asiut governorates (upper Egypt).
WPV type 3 has not been reported since December 2000. The genetic evidence
of surveillance gaps, most pronounced in Chad and Sudan, where low-intensity
WPV type 1 and type 3 circulation went undetected for prolonged periods,
is of substantial concern because of its implications for the final precertification
phase of polio eradication (CDC, unpublished data, 2005). All countries
must closely monitor surveillance quality by using performance indicators
for subnational areas to detect and correct any remaining problems affecting
surveillance sensitivity; this will ensure rapid detection of circulating
virus or importation and timely responseref.
The above discussion on the identification of undetected WPV type 3 circulation
through routine surveillance in Chad and Sudan raises concerns that a similar
situation may exist in nearby countries, either because of recent reinfections
with WPV type 1 or the ongoing outbreaks in the Sudan. Hence, an added
caution that the use of mOPV type 1 may need to be followed by mOPV 3 at
a later date. While Somalia has not reported a case since October 2002,
preventive immunization campaigns were conducted in February and March
2005, and are being evaluated for any potential areas of low coverage.On
Aug 16 there were 415 confirmed cases across 12 of the 22 governorates
of the country have reported cases, 75% in Hodeidah. This focalization
suggests that the preventive campaign in April 2005 helped prevent even
further spread. The next SIAs in Yemen occurred on 11 Jul 2005. There were
a total of 478 cases reported in this outbreak, which is now considered
under control. The date of onset of the last reported case was 17 Nov 2005
Indonesia (the 16th previously polio-free countries have reported
new cases) : a 18-month-old girl in Giri Jaya village, Sukabumi
District, West Java, about 100 km (62 miles) south of Jakarta, had onset
of paralysis on 13 Mar 2005 and was diagnosed with acute flaccid paralysis
from wild poliovirus type 1 isolate on April 21. She was previously un-immunized.
Genetic analysis of the virus demonstrates that its origin is West Africa,
similar to the viruses which caused the 2003/2004 outbreak. Further analysis
suggests the virus traveled to Indonesia through Sudan (99.1% similar),
and is 99.2% similar to recently isolated viruses in Saudi Arabia and Yemen.
The most likely explanations of how it got there are that it either was
brought back by an Indonesian working in Saudi Arabia or by a pilgrim who
went to Mecca in January 2005 : no relatives of the child had gone to areas
where polio was endemic, but other families in the village had members
who had gone recently to Saudi Arabia as workers or pilgrims. The case
– the first since 1995 – prompted government health workers to undertake
house-to-house vaccinations in 4 neighbouring villages, intensify surveillance
and eventually vaccinate 5.2 million children under 5 by July. An outbreak
response immunization (ORI) was immediately performed in 4 villages in
the immediate area of the case, reaching 4000 children aged < 5 years.
The intensified AFP surveillance has detected 7 additional AFP cases in
the village of the index case -- these are now under investigation. A 2nd
polio case was reported on 4 May 2005 by government sources : a 20 months
old boy living in the same village as the 1st case. Genetic analysis
has not yet been carried out on the 2nd case, but it is extremely likely
that the 2 are related viruses. 2 rounds of mopping-up immunization for
all children aged < 5 years in West Java, Banten and Jakarta Provinces
will be conducted, to ensure that any transmission of wild poliovirus is
rapidly interrupted, and to rapidly improve population immunity over a
wide area of Java. The rounds should be conducted end-May and end-June,
targeting approximately 6.4 million children under the age of 5 years :
the 2nd round of a nationwide anti-polio
vaccination campaign had fewer takers because of parents' fears of
possible harmful side effects. 2 more rounds are scheduled for 30 Aug
2005 and 27 Sep 2005, targeting 24.3 million children. Extension of
this activity to cover other areas (and possibly nationwide) will depend
on the results of intensified active surveillance in the other provinces,
and determination of wider spread. The costs of the mopping-up campaign
are as follows: vaccine costs USD 1.17 million and operations costs USD
1.2 million. The Ministry of Health conducted national mmunization campaigns
each year from 1995 to 1997, followed by sub-national immunization campaigns
in 1999, 2000 and 2001. A further national campaign was implemented in
2002 to maintain high levels of immunity in children. Routine polio immunization
coverage of infants has been consistently above 90% nationally, although
this average masks pockets where coverage is considerably lower (55% in
Western Java). Indonesia's surveillance system for paralysis in children
is meeting globally recognized minimum standards, and a review by a team
of international experts in June 2003 found that surveillance was adequate
to detect wild poliovirus transmission. Resistance to polio vaccine has
been high from northern Nigeria to the Pakistan frontier because of persistent
rumors that it is a Western plot to render Muslim girls infertile or to
spread AIDS. Paradoxically, after several states in Muslim northern Nigeria
halted vaccinations in 2003, it was purchases of Indonesian vaccine that
persuaded wary imams and politicians to drop their opposition, because
it is a Muslim country. Indonesia is a large chain of islands, and parts
of it, including northern Sumatra, are in rebellion against Jakarta's rule.
When polio gets into war-torn areas, as it has in Sudan and Ivory Coast,
it can become much harder to eliminate. Until recently, Indonesia also
lacked a polio emergency plan that provides for vaccinating at least half
a million children within 4 weeks of finding a case, going house to house.
A 20-month-old girl named Selvi, has been brought to Jakarta by her family.
As of 30 Sep 2005, globally there have been 300 cases of which 21 are type
1 Vaccine-Derived Polioviruses (VDPV) from Madura Island in East Java.
The remaining isolates identified have been wild poliovirus type 1. A total
of 35 regencies in 10 of the country's total of 32 provinces are affected
:
54 in West Java province :
18 in the district of Sukabumi, where the 1st case was identified
4 in the district of Bogor
24 in the Lebak province (Banten and Serang districts)
in Sumatra
15 in Lampung province (Tanggamus district)
1 in the district of Cianjur
1 in Demak district in Jawa Tengah
4 in DKI Jakarta (Central Jakarta) province
The identification of a case of polio in Lampung Province on the island
of Sumatra is disappointing news. All prior cases had been in Provinces
on the island of Java. Geographically, Lampung Province is the closest
to the island of Java, near Banten and Jakarta Provinces. The "good news"
is that there have not been further reports of cases on other islands (outside
of Java) in the Indonesian archipelago since the report of the 2 cases
on Sumatra in early July 2005. From 31 May to 2 Jun 2005, a polio immunization
"mop-up" campaign was conducted, covering West Java, Banten and Jakarta
provinces, to reach 6.4 million children under the age of 5 years. Planning
for the 2nd-round campaign (to be held on 28-29 Jun 2005) has begun. The
findings of the investigation suggest a recent introduction of wild poliovirus.
The island of Java is the most populated island in the Indonesian archipelago.
Provincial population statistics for 2000 from the Bureau of Population
Statistics of Indonesia, the estimated population of West Java (Jawa Barat)
was 35 729 537, Jakarta was 8 389 443, Central Java 31 228 940, Banten
8 098 780, and Lampung was 6 741 439 -- these 5 provinces represent approximately
44 percent of the population of the countryref.
Provincial-level mop-up activities in the originally affected provinces
has not prevented spread to additional provinces. One wonders at what point
there will be the re-institution of national immunization days as part
of the response to this outbreak. Further information from the Polio eradication
website update on this outbreak mentions that "genetic analysis of the
virus demonstrates that its origin is in West Africa, similar to the viruses
which caused the 2003/04 outbreak. Further analysis suggests the virus
traveled to Indonesia through Sudan, and is similar to recently isolated
viruses in Saudi Arabia and Yemenref.
Hence, it appears as though the geographic spread from the original outbreak
in Nigeria is continuing. Indonesia plans to hold a nationwide vaccination
campaign on 30 Aug 2005 and 27 Sep 2005 in all 33 provinces in the country
to halt the spread of the disease, targeting 24.4 million children under
5 years old.
No cases was reported since Sep 7, but 5 new poliovirus cases were
confirmed on 19 Oct 2005 from Aceh (NAD), South Sumatera, Lampung and Riau
provinces on Sumatra Island. These 2 provinces are geographically separated
from Lampung, the most southerly province on Sumatra Island, suggesting
significant spread of the wild poliovirus on the island of Sumatraref.
While coverage during the last national vaccination day was reported to
be high (97% of the targeted population), there is always the likelihood
that there are persistent low coverage "pockets of susceptibles" that are
not reached during the campaigns
11 new VDPV cases were reported from Madura Island, East Java province.
This brings the total number of polio cases to 342 (including 45 type
1 VDPV, under investigation, from Madura Island in East Java province).
A total of 10 provinces and 43 districts are affected. In addition to the
2 emergency vaccination campaigns (OPV Mop-ups rounds conducted on 31 May
and 28 Jun 2005 in West Java, Banten and Jakarta provinces), 3 rounds of
National Immunization Days (NIDs) were held on 30 Aug, 27 Sep and 30 Nov
2005. Over 24 million children less than 5 years of age were targeted throughout
the country. Prior to this outbreak (caused by an importation of type 1
wild poliovirus), Indonesia had been polio free since 1995. According to
the polio eradication website case report listing, as of 3 Jan 2006, the
date of onset of the most recent confirmed case in Indonesia is 25 Nov
2006
Angola (polio-free since 2001) : on 24 Jun 2005, the Ministry of
Health of Angola reported polio in a 17-month-old girl with a previous
history of taking oral polio vaccine (OPV) developed fever and paralysis
in both legs on 25 Apr 2005, in the metropolitan area of the capital, Luanda.
Genetic sequencing of the type-1 wild poliovirus shows that it originated
in India. Virological and epidemiological evidence suggest a recent importation.
The affected child and her family have no travel history. An investigation
did not detect spread beyond the community. Outreach from routine immunization
services has been stepped up in advance of the campaign. The national routine
immunization coverage of children against polio is estimated to be 45%.
A nationwide polio vaccination campaign is planned 29-31 Jul 2005. Authorities
are considering the use of a combination of monovalent oral polio vaccine
(mOPV) in the immediate area of the case and trivalent oral polio vaccine
in the rest of the country for maximum impact. This will be followed by
another round in August. Health authorities have immediately intensified
Acute Flaccid Paralysis (AFP) surveillance in the infected district and
surrounding areas and WHO/African Region has notified neighbouring countries.
Briefings with all community and religious leaders, non-governmental organizations
and traditional healers are taking place in all municipalities of Luanda.
Angola's last polio case was in September 2001. An outbreak of over 1000
cases in 1999 was met with repeated supplementary immunization, and by
2000, cases were down to 55. The municipality Cacuaco reports a routine
OPV coverage of 50% and has an AFP surveillance rate of 2.1. In Luanda
generally, the AFP rate over the past 12 months is 1.25. Supplementary
immunization activities and funding: The Ministry of Health, Angola, supported
by the Global Polio Eradication Initiative partners, had already planned
for 2 National Immunization Days in July and August to protect Angola's
polio-free status. These campaigns, requiring external financing of USD
3.74 million, are supported by the US Centers for Disease Control and Prevention,
the Canadian International Development Agency, the European Commission,
USAID and the governments of Spain and Portugal. Any eventual 3rd round
of campaigns would require an additional USD 1 million in external funding.
Importations such as this and other recent ones into Indonesia and Yemen
underline the importance of stopping transmission in endemic countries
with indigenous poliovirus. Until polio is eradicated everywhere, all countries
remain at risk. To stop transmission in the endemic areas, prevent further
spread and protect polio-free countries, supplementary immunization activities
need to be stepped up. For this, the Global Polio Eradication Initiative
requires USD 50 million by the end of July 2005 and multi-year pledges
to enable activities in 2006-2008, of which UDS 200 million is needed by
2006. The funding shortfall is a major risk to global polio eradication.
Outbreaks and importations place further stress on available resources.
The occurrence of an "imported" case of polio in Angola is yet another
setback for the global polio eradication effort. The identification of
the virus as one originating in India is a reminder that India is still
an endemic area for wild poliovirus activity, even though there has been
major progress (to date there have been 18 confirmed cases in India for
the year 2005, with 134 cases confirmed in 2004, 225 cases confirmed in
2003, 1600 cases confirmed in 2002ref).
While this case is being classified as "imported," the absence of a history
of travel of the case means that there has been local transmission of a
wild poliovirus imported from India in the general area where the case
lives. With an overall country-wide vaccination coverage of 45%, it is
wise that the "mop-up" activities in response to this case will be at the
national level. That this case had date of onset in late April 2005 and
no additional cases have been identified may be good signs, although there
is not mention of additional AFP cases currently under investigation. Of
note, an adequate AFP surveillance rate is a non-polio AFP rate of at least
1/100 000 population. According to the statistics presented above, AFP
surveillance is adequate in the affected areas. The appearance of a 2nd
case in ithe port city of Lobito, some 400 miles (644 km) south of the
capital city of Luanda (where the 1st case was detected) is circumstantial
evidence of significant spread of the poliovirus. As a reminder,
the ratio of paralytic to non-paralytic infections ranges from 1:50 to
1:1000 with an average of 1:200 (for every one paralytic case identified
there are an average of 200 individuals infected with the wild poliovirus
who show no signs of paralysis). Hence, the appearance of 2 cases
suggests there have probably been at least 400 others infected with the
wild poliovirus in the country. It is not known whether the cases had known
traceable contacts (narrowing down the range of probable infected individuals)
or whether they were unrelated epidemiologically. That the virus
strains are genetically linked is further evidence of local transmission
of the wild poliovirus. As of 23 August 2005, 7 cases of polio have been
reported. 5 provinces have been affected: Bengo, Benguela, Luanda, Lunda
Sul, and Moxico. The most recent case, in Benguela, had an onset of 12
Jul 2005. This case occurred before the 1st National Immunization Day (NID)
campaign on 29 Jul 2005. A 2nd NID was held on 26 August. In order to ensure
rapid interruption of the virus transmission in Angola, a 3rd round of
NIDs has been planned for late September 2005. It would be recalled that
Angola witnessed one of the largest polio epidemic outbreaks in Africa
in 1999 with about 1117 children paralyzed and leaving 113 dead. Technical
and financial support provided by the partners over the years enabled the
country to become polio-free since September 2001. The importation of this
virus constitutes a major threat not only to the country but to the entire
region in the drive to interrupt poliovirus transmission by the end of
December 2005. If this transmission is not halted in the next 4 months,
Angola would have re-established wild poliovirus transmission. Failure
to halt transmission could also lead to spread of virus to neighboring
countries such as Republic of Congo, Democratic Republic of Congo, Namibia
and Zambia or even beyond the confine of the sub-region or regionref
Somalia (polio-free since 2002) : a 15-month-old girl from Mogadishu
had onset of paralysis on 12 Jul 2005. Genetic sequencing is ongoing to
determine the origin of the virus. On 13 Sep 2005, the Global Polio Eradication
Initiative -- spearheaded by the World Health Organization (WHO), Rotary
International, the US Centers for Disease Control and Prevention (CDC)
and UNICEF -- launched a large-scale series of immunization campaigns coordinated
across 8 countries: Somalia, Ethiopia, Yemen, Sudan, Eritrea, Djibouti,
and parts of Kenya and the Democratic Republic of the Congo -- between
September and November 2005. The campaigns will reach more than 34
million children with multiple doses of polio vaccine and rapidly boost
population immunity in the Horn of Africa. The rapid and large-scale response
is largely possible due to a USD 25-million grant provided by the Bill
& Melinda Gates Foundation, and support by other donors including the
Humanitarian Aid Department of the European Commission (ECHO). The 1st
phase of the plan is being launched on 28 Sep 2005 in Somalia, where 1.5
million children under the age of 5 years will be targeted for immunization.
To maximise the impact of the campaigns, some of the countries will be
using the recently-developed monovalent oral polio vaccine type 1 (mOPV1).
Licensed earlier in 2005, also with support by the Bill & Melinda Gates
Foundation, mOPV1 offers higher protection against poliovirus type 1, the
specific virus currently affecting the Horn of Africa, with fewer doses
than traditional trivalent polio vaccine. The ongoing polio epidemic (total
131
cases) has spread outside the capital Mogadishu. Somalia is the only
country in the world with a geographically expanding polio outbreak. With
recent confirmation of cases outside Mogadishu, including in the north
of the country, the risk remains of continued spread of wild poliovirus
in Somalia, and potential for spread to neighboring countries. Polio immunization
campaigns are planned for Jan and Feb 2006, aiming to reach each time the
country's 1.6 million children under 5 years of age. Somalia, a country
plagued by ongoing conflict, insecurity, the lack of a health infrastructure
and low rates of population immunity, is at the top of the Global Polio
Eradication Initiative's list of acute challenges. Recognizing the threat
of poliovirus importations due to polio outbreaks in nearby Ethiopia, Sudan
and Yemen, Somalia had previously conducted 3 NIDs before the 1st polio
case of the outbreak in July 2005. These preventive campaigns have been
instrumental in limiting the spread of the virus following importation.
5 NID have been conducted since the start of the outbreak and have limited
the geographic spread of the virus. 4 of these campaigns used the powerful
new monovalent oral polio vaccine. A review of management and operations
in the country was conducted in November 2005 in order to guide action
and limit the outbreak. To overcome the constant constraints of insecurity
and inaccessibility, WHO and UNICEF work in close collaboration with communities
and local officials on the polio eradication effort. The program employs
198 national and 10 international staff. During immunization campaigns,
additional community members are recruited to assist in vaccination, logistics,
social mobilization and security. With sufficient funding, additional immunization
activities will be conducted in early 2006, and the outbreak could be stopped
by 31 Mar 2006.
Eritrea :
Namibia (considered polio-free in the early 1990s but saw an outbreak
of 53 cases of the disease in 1993, spurring another immunisation drive.
Its most recent case was reported in 1995) : a suspected polio outbreak
has caused 34 suspected cases (3 laboratory confirmed) and 7 deaths
(5-laboratory confirmed) () since early May 2006. Most cases
were reported in the Katutura township outside Windhoek but the 1st case
was reported at Aranos district, about 395 km from the capital, in early
May 2006ref1,
ref2,
ref3.
The 39-year-old farmer ad been in Windhoek 2 weeks before for a cholecystectomy
(admitted on 25 Apr for surgery on 27 Apr). He had not traveled outside
Namibia in the last 2 months. Childhood vaccination history could not be
obtained. He returned to Aranos over the weekend of 29/30 Apr, where he
recovered well. On 6 May he fell ill with rigors, shortness of breath and
abdominal pain, the day before he presented with paresis. A provisional
diagnosis of sepsis was made. As he also presented with paresis of both
legs to the extent that he could not walk; a stool specimen was sent for
polio diagnosis. He did not complain of any muscle pains but was severely
ill. He was referred to Windhoek where he was hospitalised and immediately
needed intubation and ventilation for respiratory failure; weakness of
intercostal muscles was noted. Polio virus wild type 1 was isolated from
the stool sample and showed it to be similar to that seen in Angola in
2005, with an original origin in India. There is a temporal and geographic
relationship between this case and the current AFP outbreak in Windhoek
: the patient was hospitalised in Windhoek 2 weeks before paresis set in.
The Nossob River that drains an area next to Windhoek flows past Aranos
but it largely remains submerged in the Khalagadi sand except during the
rare flood; although Aranos makes use of borehole water it seems a very
unlikely source of infection, due to the distance from Windhoek. It is
possible that abdominal surgery adversely affected the degree of paralysis
in this case, since it has been reported that tonsillectomy is associated
with bulbar paralysis in children prior to symptomatic polio or injection
in a limb prior to illness is associated with severe paralysis in the same
limb. The mention of the possible association of more severe disease with
respiratory paralysis following surgery during the incubation period was
observed in earlier years when polio was a significant problem, as was
the association of paralysis in a limb that had received an injection during
the incubation period, and both have been reported with the oral vaccine
(Bosley et al. Provocation poliomyelitis: vaccine associated paralytic
poliomyelitis related to a rectal abscess in an infant. J Infect 2003,
47:82; Strebel et al. Intramuscular injections within 30 days of immunization
with oral poliovirus vaccine--a risk factor for vaccine-associated paralytic
poliomyelitis. N Engl J Med 1995 332: 500). In the same days 5 people
have died from an as yet unnamed disease : the 1st case had been reported
on 7 May 2006 in Aranos, a small town south of Windhoek, and the patient
was still on ventilator support. Initially, the disease was confirmed in
3 informal settlements in Katutura, the capital's oldest township, but
it had also been found south of Windhoek in the Karas Region and to the
north in the Otjozondjupa Region. Initial fears were that the disease was
Guillain-Barre syndrome or a polio outbreak, but tests have ruled out both
of these. Windhoek Central Hospital (WCH), Namibia's biggest referral center,
is caring for 17 people ranging from 14 to 55 years old, one of whom is
in critical condition, with 15 others at Katutura State Hospitalref.
Namibia 's AFP surveillance rate is 2.6 per 100 000 children under
the age of 15 years, and the adequate stool collection rate is 86% (AFP
surveillance rates < 1.0, and adequate stool collection rates < 80%
would mean that a country would not be able to rapidly detect polio re-infection).
In Namibia, 82% of children < 1 year of age have been routinely immunized
with at least 3 doses of oral polio vaccine (OPV) (routine immunization
rates < 90% leave a population at substantial risk of an outbreak in
the event of a polio re-introduction). Given the age range of the cases
(14-55 years), there is the suggestion of a growing pool of susceptibles
in Namibia through the years, hence the decision to include the entire
population in the 1st round of the planned National Immunization Day (NID)
is a prudent measure. The government is planning an immunization response
consisting of 3 National Immunization Days (NIDs), using monovalent oral
polio vaccine type 1 (mOPV1). The 1st NID could be conducted as early as
21 Jun [2006] and will aim to reach the entire population of the country
(2 million) rather than the usual under-5-years population. The age of
any further cases will dictate the target age groups for the 2 subsequent
NIDs. The age range of cases is more consistent with a background picture
of reduced WPV transmission in earlier years preceding the interruption
of transmission in 1995, probably attributable to widespread vaccination.
In that setting, older susceptibles have "slipped through the cracks" of
the national immunization days in the 1990's targeted at children <
15 years of age. As a reminder, the last outbreaks of polio in the Netherlands
and in the USA have involved a large proportion of adult cases as well,
related to large pools of adult susceptibles (in both cases associated
with populations that refused vaccination due to religious objections).
These populations were living in countries where they were surrounded by
vaccinated individuals providing herd immunity through the years until
the WPV was "lucky" enough to find entry into those pockets of susceptiblesref1,
ref2,
ref3,
ref4,
ref5.
Hopefully, in the case of Namibia, the response to the NID campaign will
be high, permitting an interruption of transmission of the WPV.
Myanmar (last confirmed case of WPV-associated polio in Myanmar
(prior to this case) had date of onset of paralysis on 13 Feb 2000): a
wild poliovirus (WPV) was isolated from an importation case with onset
of paralysis on 9 Apr 2006ref.
Singapore : isolation of a wild poliovirus (WPV) from an imported
case with onset of paralysis on 23 Apr 2006ref
Nepal (all cases from 2005 onward are importation-related) : a new
polio case was reported from the west-central region in the interior of
the country. It is the 1st case of wild poliovirus transmission in
the country in 2006. Classification of a 2nd case -- from a contact
(close to the border with Bihar state, India) -- remains outstanding.
Both cases are undergoing genetic sequencing to determine their origins.
An appropriate outbreak response to these most recent cases is currently
being finalized
Bangladesh : an imported case in 2006, genetically similar to WPVs
identified in Uttar Pradesh India
Globally, as of the week of 22 Jun 2004, 333 cases of polio were
reported worldwide, with 257 cases in Nigeria (77.2% of the global reports),
18 cases in Niger (5.4%), 15 cases in Pakistan (4.5%), 13 cases in India
(3.9%), 3 cases in Afghanistan (1%), and 1 case in Egypt (0.3%). These
6 countries are those countries where polio is considered to be endemic
(wild poliovirus transmission has not been interrupted) and account for
307 of the 333 reported cases in 2004 (92.2% of the reported cases globally).
Of the remaining 26 reported cases, all are from countries in Africa and
are related to the ongoing outbreak in Nigeria. (1 is from the Central
African Republic, 4 are from Burkina Faso, 4 are from Benin, 8 are from
Cote d'Ivoire, 7 are from Chad, 1 is from Botswana, and 1 is from Sudan).
Since
Jan 1 to 24 Aug 2004, there have been 602 cases reported globally,
in the following endemic countries: Nigeria (476 cases), India (34), Pakistan
(23), Niger (19), Afghanistan (3), Egypt (1); and the following importation
countries: Chad (12), Cote d'Ivoire (9), Burkina Faso (6), Benin (6), the
Sudan (5), the Central African Republic (3), Mali (2), Guinea (1), Cameroon
(1), Botswana (1). The poliovirus is now endemic in only 6 countries, down
from > 125 when the Global Polio Eradication Initiative was launched in
1988 : the 2004 reported cases included
Asia
Afghanistan
India
Pakistan
Africa
Egypt : 1 case
Nigeria : 786 cases (> 2/3 of polio cases worldwide)
Niger : 25 cases
Since mid-2003, 13 countries have suffered importations of wild poliovirus
linked to virus circulating in northern Nigeriaref.
Benin : 6 cases
Botswana : 1 case
Burkina Faso : 9 cases
Cameroon : 13 cases
Central African Republic : 30 cases
Chad : 23 cases
Cote d'Ivoire : 17 cases
Guinea : 5 cases
Mali : 18 cases
Sudan : 124 cases (with 1 case reported in 2005)
In 4 of these countries (Burkina Faso, Chad, Cote d'Ivoire and the Sudan)
wild poliovirus transmission has been re-established (i.e. continued circulation
for >6 months). These 4 countries had interrupted poliovirus circulation
prior to the re-seeding related to the outbreak in Nigeria
The latest official count of polio cases reported to WHO as of 11 Oct
2005 is as follows:
Yemen (importation) 472
Nigeria (endemic) 489 (43%)
Indonesia (importation) 264
India (endemic) 37
Sudan (re-established transmission) 26
Ethiopia (importation) 17
Pakistan (endemic) 15
Angola (importation) 8
Afghanistan (endemic) 4
Niger (endemic) 4
Mali (importation): 3
Somalia : 3
Cameroon (importation) 1
Chad (re-established transmission): 1
Eritrea (importation) 1
Nepal : 1
(Egypt (endemic) 0)
global cases of poliovirus: 1349 (96% in member countries of the Organization
of the Islamic Conference (OIC))
One worries about other at-risk countries where (1) acute flaccid paralysis
(AFP) surveillance may be weak and (2) pockets of susceptible populations
have increased; as many countries stopped conducting national immunization
days after they had interrupted transmission of wild
poliovirus.
But despite flare-ups in 16 new countries, polio eradication officials
are still optimistic. Some even hope that the last new case of paralysis
will be found in 2005. Even if that happens, the earliest that polio could
be declared eradicated would be 2008, because World Health Organization
guidelines mandate 3 case-free years. Transmission has been re-established
in 2 countries where civil wars complicate vaccination drives, Ivory Coast
and Sudan. Cases have been found in Ethiopia, which is crowded, poor and,
like many other countries, stopped vaccinating when polio was wiped out.
Nevertheless, smallpox was eradicated there. In very rare cases, the weakened
virus in the vaccine can mutate into a "wild type" virus that paralyzes
and kills. Such a mutant caused a polio outbreak in Haiti and the Dominican
Republic in 2000. Also, a small number of people have unusual genes that
shed such mutant viruses for years or decades. The chance that both those
rare events will combine is very small, but it is not zero. One frustration
for medical detectives is that the science of polio-hunting forces them
always to be a few weeks behind the virus because only 1 case in 200 is
symptomatic, further requiring differential diagnosis with several other
diseases, including Guillain-Barre syndrome, meningitis and even severe
malaria or diarrhea. There is no simple blood test : instead, 2 stool samples
must be collected 24 hours apart, put on ice -- not always easy in rural
areas -- and shipped to a reference laboratory. In Yemen's case, the nearest
one is in neighboring Oman. The virus must then be grown for about 2 weeks.
If it is positive, it is shipped to a more advanced laboratory -- in Yemen's
case, to Cairo -- for regrowth and tests to distinguish wild-type polio
from vaccine strains. The whole process can take 60 days. To do genetic
typing, which identifies the strains that the virus is related to, the
samples must be shipped and grown again. Only a handful of laboratories
do such work. Among those that do are laboratories at the Centers for Disease
Control and Prevention in Atlanta, USA, & some of its counterparts
in Europe, South Africa, Japan and China. Each confirmed case requires
a major response. Even in tiny Yemen, the country plans to vaccinate all
5 million of the youngest children at least 3 times this year, and there
must be a 40-day wait between each round. Thousands of "volunteer" vaccinators
must be recruited, though many are actually paid small stipends from WHO
emergency funds. Transportation to take teams into rural areas must be
arranged. Since the vaccine must be kept refrigerated, a "cold chain" must
be set up. That means refrigerators in every rural corner of the country,
and freezers for the blocks of ice that vaccinators put in their plastic
foam shoulder boxes. In the West, this is routine; in countries where electricity
is nonexistent or sporadic, it means generators to run the freezers and
fuel to run the generators. In poor countries, the public health system
must drop almost everything else, like care for pregnant women and measles
vaccination. One should also be concerned about polio transmission in countries
where acute flaccid paralysis (AFP) surveillance isn't optimal. This
current outbreak in Indonesia has potential implications in other countries.
The origin of the virus was most likely Saudi Arabia (that is, the origin
prior to arrival in Indonesia). This suggests that either guest workers
(from Indonesia in Saudi Arabia) or hadj pilgrims from Indonesia to Saudi
Arabia) were "responsible" for the introduction of the wild poliovirus
into Indonesia. Either explanation suggests other countries are at risk,
as there are guest workers in Saudi Arabia from many countries including
those in the subcontinent (most notably Bangladesh, which has interrupted
wild poliovirus transmission), Indonesia, the Philippines, possibly Malaysia,
and of course, the hadj pilgrims come from all over the world. When polio
is imported, countries have to hustle : if they don't, they get endemic
transmission. But as long as the resources hold out, we can support these
countries. Success is so close. It would be a shame to see it fail.
The Global Polio Eradication
Initiative (GPEI) is spearheaded by the WHO, Rotary International,
the US CDC and Prevention and UNICEF : it is the world's largest public-health
initiative. The polio eradication coalition includes governments of countries
affected by polio; private sector foundations (e.g. United Nations Foundation,
Bill & Melinda Gates Foundation); development banks (e.g. the World
Bank); donor governments (e.g. Australia, Austria, Belgium, Canada, Denmark,
Finland, France, Germany, Ireland, Italy, Japan, Luxembourg, the Netherlands,
New Zealand, Norway, Portugal, the Russian Federation, the United Kingdom
and the United States of America); the European Commission; humanitarian
and nongovernmental organizations (e.g. the International Red Cross and
Red Crescent societies) and corporate partners (e.g. Aventis Pasteur, De
Beers, Wyeth). Since 1988, some 2 billion children around the world have
been immunized against polio, involving the cooperation of > 200 countries
and 20 million volunteers in developing countries, US$3 billion in spending
(including more than US$ 600 million committed by Rotary International),
with the global goal of eradicating polio by 2005. Responding to this looming
epidemic will require an additional US$ 100 million, of which US$ 25 million
is urgently required by August 2004 for the 1st campaign. > 200 places
are now polio-free. Since 1996, supplemental immunisation activities
(SIAs) targeting children aged <5 years have been conducted annually
in Nigeria. National Immunization Days (NIDs) (nationwide mass campaigns
during a short period (days to weeks) during which 2 doses of OPV are administered
to all children (usually aged <5 years) regardless of previous vaccination
history, with an interval of 4-6 weeks between doses) were conducted annually
through 2002. In February and March 2004, 2 NID rounds were conducted,
targeting all 37 states (36 states plus one Federal Capital Territory [FCT]).
All states except Kano and Zamfara took part in the February round, and
all except Kano took part in the March round. Tens of thousands of volunteers
embarked on an emergency campaign on Feb 23 to immunise 63 million children
against polio in 10 African countries (Benin, Burkina Faso, Cameroon, Central
African Republic, Chad, Cote d'Ivoire, Ghana, Niger--where polio is still
endemic--, Nigeria and Togo) at a cost of $10m following a fresh outbreak
in neighbouring Nigeria (347 cases in 2003); anyway several influential
Muslim leaders in northern Nigeria have questioned the safety of the oral
polio vaccine (vaccines may be part of a US plot against Muslims and could
be contaminated with traces of oestrogen and progesterone to make women
infertile or to infect people with the virus that causes AIDS), causing
officials in the 3 predominantly Muslim states of Kano (which last conducted
a SNID in Apr 2003), Kaduna, and Zamfara, and (to a limited extent) in
Niger state to suspend all SIAs since August 2003 and to cancel a key 4-day
immunization
drive for 23 of the 63 million children : but even before the ban, the
lack of routine medical services in the impoverished state meant that as
few as 16% of the 3 million children under age 5 years were sufficiently
immunised. Tests in South Africa and India proved the rumours unfounded
in mid-Mar 2004, but in the meantime the virus crept across Nigeria into
previously polio-free countries, such as Chad, Ghana and Togo. Some Muslim
leaders also have said that even if the vaccine is safe, they will boycott
the immunizations simply because the United States is a major funder in
polio eradication; they say it is their way of protesting US wars in the
predominantly Muslim countries of Afghanistan and Iraq. On early March
2004, the WHO confirmed new outbreaks in Benin and Cameroon. In 2003, 9
rounds of Subnational Immunization Days (SNIDs) were conducted,
targeting northern states where polio is endemic. The number of participating
states and target population varied in each SNID, with the number of children
vaccinated ranging from 3.6 to 15.0 million. 12 states with endemic disease
(Bauchi, Borno, Gombe, Jigawa, Kaduna, Kano, Katsina, Kebbi, Niger, Sokoto,
Yobe, and Zamfara) and FCT took part in at least 2 rounds of SNIDs during
2003. Reported coverage at the state level during these SNIDs ranged from
56-100%. In addition, during 2003, 4 rounds of mop-up vaccination activities
were conducted in Nasawara state and 2 rounds each in Benue and Kogi, sites
that had been re-infected with WPV after being polio-free for >12 months.
Reported coverage in these states during these mop-up activities ranged
from 86-100%. During 2002--2003, the number of confirmed WPV in Nigeria
increased from 202 to 355. Of these, 192 were PV1, and 163 were PV3. In
2003, a total of 23 of 37 states reported at least one WPV, representing
a wider area of circulation than in 2002, when 15 states reported WPV.
Of these 23 states, 13 are considered to have endemic transmission, whereas
10 were re-infected after being polio-free for >12 months. Early in 2004,
PV1 was reported from Anambra state, one of 14 southern states that had
remained polio-free in 2003. In 2003, 25% of the Nigerian cases centered
in Kano : of 89 WPV cases in Kano, 57 (64%) were associated with PV3 and
32 (36%) with PV1. Virus sequence data indicated that the PV3 virus radiated
outward along multiple independent chains of transmission. This outbreak
started in March. The PV1 outbreak started in May, at the onset of high
transmission season. A second peak of PV3 cases occurred in August, when
numbers of PV1 and PV3 cases were equal. Of 355 polio cases reported in
2003, a total of 81 (23%) occurred in children aged >3 years, of which
69 (85%) were either never or incompletely vaccinated. Of the 18 genetic
clusters (corresponding to groups of related chains of transmission) observed
in Nigeria in 2002 (14 PV1 and 4 PV3), 7 were not observed in 2003 (6 PV1
and one PV3). However, the large outbreaks in 2003 have increased the genetic
diversity of several clusters such that some previous PV1 clusters have
expanded into at least 4 new genetic clusters, indicating intense transmission.
Financial support is also a recurrent problem : in 2003, cash-flow crises
forced most polio-free countries to stop their immunization campaigns.
This left millions of children vulnerable to infection from neighbouring
endemic countries. On Tue 13 Apr 2004 health investigators confirmed a
new case in a 7-year-old boy in Ngami in northeastern Botswana recovering
from paralytic poliomyelitis -- the 1st case in southern Africa since 1997
-- that they linked to type 1 poliovirus imported from northern Nigeria
3000 miles away. Botswana had a non-polio AFP reporting rate of 2.3 per
100 000 population in 2003, with 16 cases of AFP reported, and, 75% with
adequate stool specimens submitted for viral isolation studies, of which
none were positive. To May 2004, in 2004, Botswana has reported 6 AFP cases,
out of which, one had a type-1 poliovirus identified. The occurrence of
2 additional suspected cases of polio in Botswana, following this 1st case,
are cause for concern, but they may just be part of the observed background
non-polio AFP illness that occurs in Botswana. This is now the 9th formerly
polio-free country to have been re-infected as a result of ongoing poliovirus
transmission in Nigeria : the other 8 countries are: Benin, Burkina Faso,
Cameroon, Central African Republic, Chad, Cote d'Ivoire, Ghana, and Togo.
Botswana officials in response plan to conduct 2 rounds of house-to-house
immunizations nationwide starting in May 2004 involving all children under
the age of 5. They hope to reach 250 000 children, at a cost close to USD
1 million. An extra US$150 million is needed to fill the remaining funding
gap for activities between 2004 and 2005. During 2003, the proportion of
nonpolio AFP cases in children aged <5 years who had received >3 doses
of OPV was <60% in 12 of 13 states (median: 33%; range: 9-75%) where
polio is endemic. The proportion of nonpolio AFP cases in children aged
<5 years who had received >3 doses of OPV was <60% in 5 of 8 re-infected
states, but in only one of the 14 states without endemic disease. Statistics
for Nigeriaref
: Year / AFP / Non-polio AFP rate / AFP cases with adequate specimens /Total
confirmed polio cases / Wild-virus confirmed polio cases
1996 / 942 / 0 / 0 / 942 / 0
1997 / 5 / 0.01 / 20 / 383 / 1
1998 / 489 / 0.4 / 40 / 312 / 42
1999 / 1242 / 0.5 / 26 / 981 / 98
2000 / 979 / 0.7 / 36 / 638 / 28
2001 / 1937 / 3.8 / 67 / 56 / 56
2002 / 3010 / 5.7 / 84 / 202 / 202
2003 / 3319 / 6 / 91 / 355 / 355
2004 / 236 / 5.6 / 96 / 15 / 15
According to the WHO Polio Eradication websiteref,
"On 23 Feb 2004, a massive synchronized polio immunization campaign was
launched in 10 countries across west and central Africa (Benin, Burkina
Faso, Cameroon, Central African Republic, Chad, Cote d'Ivoire, Ghana, Niger,
Nigeria, and Togo), in an effort to immunize more than 63 million children
(Chad will begin immunization activities in March 2004). This campaign
was of critical importance to the African and global
polio eradication effort. An ongoing outbreak of polio originating
in northern Nigeria has re-infected previously polio-free areas of Nigeria
(including Lagos) as well as 8 previously polio-free countries in the region
(Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Cote d'Ivoire,
Ghana, and Togo). The outbreak was exacerbated following the suspension
of polio immunization
campaigns in several states in northern Nigeria in the second half
of 2003, resulting in a marked decrease in population immunity levels.
In 2003, Nigeria had the highest number of children paralyzed by the poliovirus
anywhere in the world, with nearly 50% of all global cases for the year
(347, as of 24 Feb 2004)." According to the WHO Polio Eradication Program
statisticsref:
Benin was polio-free during 2001 and 2002, with 2 cases confirmed in 2003
and one case in 2004. Burkina Faso was polio-free during 2000 and 2001,
with one case reported in 2002, 11 cases in 2003, and 2 cases confirmed
so far in 2004. Cameroon was polio-free during 2000, 2001, and 2002, with
one case reported in late 2003. Central African Republic was polio-free
during 2001 and 2002, with one case reported in 2003. Chad was polio-free
during 2001 and 2002, with 24 cases reported in 2003. Cote d'Ivoire was
polio-free in 2001 and 2002, with one case each reported in 2003 and 2004.
Ghana was polio-free 2001 and 2002, with 8 cases reported in 2003. Togo
was polio-free in 1999, 2000, 2001, 2003 (according to an IRIN newswire
in Oct 2003 there was one case reported in Togo in 2003ref).
The interruption of vaccination activities due to unfounded rumors of questionable
vaccine safety are regrettable, as evidenced by the reintroduction of wild
poliovirus to areas that had previously interrupted transmission. A pity
that political agendas unrelated to
health can obstruct a major effort towards disease eradication that
is so close to fruition.
in 2002 polio soared 6-fold in India and there were about 1,500 cases (>
500 cases in the state of Uttar Pradesh; 85% of all the cases in the world)
as India cut back on its immunization campaigns
since 10 November 2002 and 4 Feb 2003, 7 isolates from acute flaccid paralysis
(AFP) cases in Northern India (6 from western Uttar Pradesh and 1 from
Gujarat : there was no circulation in the community) have been found to
be closely related to the wild type 2 reference strain MEF-1, which is
used for production of inactivated polio vaccine (IPV). It is unrelated
to wild poliovirus found anywhere in the world over the past 2 decades.
MEF-1 replicates vigorously and has been one of the more common laboratory
contaminants over the years : a laboratory accident had resulted in the
contamination of a single batch of oral
poliovirus vaccine (OPV)
used in the vaccination program. It is not known whether this batch of
vaccine was contaminated at the production site, or at the vial filling
site (vaccine production results in "batches" (also known as "bulk") of
vaccine that are massed produced. These batches are then used to
fill smaller vials holding amounts of vaccine reasonable for use at vaccination
sites (ranging from single dose vials to multidose vials that can contain
as many as 100 doses). The preparation and filling of these vials can be
done at the manufacturers facility, or sometimes is done at a vaccine laboratory
in another country). Previously polio-free parts of the country succumbed
once more. Although no animals carry it, WHO earlier estimated some 10,000
laboratories worldwide carry stocks of the virus. According to WHO's laboratory
action plan, laboratories retaining wild poliovirus, infectious materials,
or potential infectious materials will eventually be requested to establish
enhanced BSL-2 (BSL-2/polio) measures for safe handling.
Copyright © 2001-2005 Daniele Focosi.
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