CSU 52/2010: FOUR ON POLIO: BILL GATES, POLIO IN TAJIKISTAN
|Sunday, 2nd of May 2010|
CSU 52/2010: FOUR ON POLIO: BILL GATES, POLIO IN TAJIKISTAN
Life is full of surprises. It is just a question of how we respond to them.
1) 'Gates Rethinks His War on Polio'
WALL STREET JOURNAL, APRIL 23, 2010
Bill Gates traveled to Africa last year to press for polio's defeat.
Bill Gates walked into the World Health Organization's headquarters in Geneva—for a meeting in an underground chamber where global pandemics are managed—and was greeted by bad news. Polio was spreading across Africa, even after he gave $700 million to try to wipe out the disease.
That outbreak raged last summer, and this week a new outbreak hit Tajikistan, which hadn't seen polio for 19 years. The spread threatens one of the most ambitious health campaigns in the world, the effort to destroy the crippling disease once and for all. It also marks a setback for the Microsoft Corp. co-founder's new career as full-time philanthropist.
Next week, the organizations behind the polio fight, including WHO, Unicef, Rotary International and U.S. Centers for Disease Control and Prevention, plan to announce a major revamp of their strategy to address shortcomings exposed by the outbreaks.
Nigeria is ground zero for the reemergence of polio. Now the country is making surprising headway against the crippling disease, in part thanks to an unlikely meeting of two leaders: Microsoft mogul Bill Gates, and the Sultan of Sokoto, the spiritual leader of Nigeria's 70 million Muslims. WSJ's Rob Guth reports.
"There's no way to sugarcoat the last 12 months," Bruce Aylward, a WHO official, told Mr. Gates in the meeting in the underground pandemic center last June. He described how the virus was rippling through countries believed to have stopped the disease.
Mr. Gates asked: "So, what do we do next?"
That question goes to the heart of one of the most controversial debates in global health: Is humanity better served by waging wars on individual diseases, like polio? Or is it better to pursue a broader set of health goals simultaneously—improving hygiene, expanding immunizations, providing clean drinking water—that don't eliminate any one disease, but might improve the overall health of people in developing countries?
The new plan integrates both approaches. It's an acknowledgment, bred by last summer's outbreak, that disease-specific wars can succeed only if they also strengthen the overall health system in poor countries.
If successful, the recalibrated campaign could shape global health strategy for decades and boost fights against other diseases. A failure could rank the effort as one of the most expensive miscalculations in mankind's long war with disease. Already, polio has evaded a two-decade-long, $8.2 billion effort to kill it off.
Big donors have long preferred fighting individual diseases, known as a "vertical" strategy. The goal is to repeat 1979's victory over smallpox, the only disease ever to be eradicated. By contrast, the broader, "horizontal" strategy has less well-defined goals and might not move the needle of global health statistics for years.
The polio fight is a lesson for Mr. Gates's foundation, which is funding other vaccines that could face similar setbacks. In the polio fight, his foundation backed a program that was following an outdated playbook. Polio's resurgence last year forced a major rewrite.
Mr. Gates has forged himself as a global-health diplomat following his 2008 retirement from Microsoft. He is using his star power and $34 billion philanthropy to try to push businesses, health groups and governments to improve health in developing countries.
Just as Mr. Gates introduced himself to the sultan, the lights flickered out.
"I want to welcome you to the real world—to the real third world," the sultan said to Mr. Gates from his gilded chair in the darkened room.
Men like the sultan are important allies. In 2003, Islamic leaders in northern Nigeria spread rumors that polio vaccines sterilized Muslim girls. Leaders halted vaccinations, allowing the virus to spread. The WHO said the virus eventually infected 20 countries.
By the start of last year, Nigeria was home to half of the world's 1,600 polio cases. The sultan could help get the campaign back on track.
Speaking to Mr. Gates and a room of religious leaders, the sultan declared his support for the polio fight. "We want to show you our commitment," he said. "The time you have taken to come here will not be in vain."
But he, too, questioned the wisdom of targeting one disease. "Other health issues should be looked into," the sultan said, "instead of just facing one direction with polio eradication." He ticked off tuberculosis, HIV and AIDS, malaria, cholera and a parasitic infection known as "snail fever."
After the global victory over smallpox 30 years ago, a rush of energy went into similar "vertical" attacks on single diseases. The polio program followed that approach and made great gains. Led by WHO and donors such as Rotary, the campaigns by the year 2000 slashed the world's polio cases to under 1,000 from 350,000 in 1988. Polio fighters planned to eradicate the disease by 2000.
That date came and went. But polio persisted, eating up billions of dollars.
Critics argued for a shift away from killing polio to free up money for controlling multiple diseases. In some countries, polio campaigns became an example of a functioning vaccination system even as other diseases were missed. Mr. Gates saw that himself in Nigeria.
Arriving at a Sokoto health clinic in a Toyota minivan stocked with Diet Coke, Mr. Gates stepped inside and was soon leaning on a wooden desk, flipping through children's vaccine records. "Do you know if this child had the first dose of DPT?" he asked, pointing to a record of a diphtheria vaccination of a boy who appeared to have missed a treatment. A health worker beside him didn't have an answer.
The clinic also had no hepatitis B and yellow fever vaccines, the workers said, because the government's system for supplying medicine wasn't working.
By contrast, in front of the clinic, a polio campaign was in full swing. Health workers tended coolers filled with vials of vaccine for children gathered there.
At a meeting the next day in the capital, Abuja, Nigeria's head of primary health care, Dr. Muhammad Ali Pate, reopened the vertical-vs.-horizontal debate. Even if Nigeria lowers polio cases, he said, the gains "can't hold" without a broader health-care system, he said.
Mr. Gates listened, seated behind a name tag that read "Our Guest." Dr. Pate showed a slide of a cartoon steam-engine train with cars labeled "Education" and "Disease Control." Polio should be just one car in that train, he said.
Mr. Gates didn't disagree—certainly Nigeria needs a functioning health system, he said in interviews. But it was a matter of priorities, he said. With the world so close to killing polio, countries like Nigeria should make eradication a top priority, he said. Victory would free up millions of dollars to pay for broader health improvements.
"So the benefit of finishing is huge," he said.
On the plane, Mr. Gates strategized about what else would help win the fight, balking at one religious leader's suggestion: forced vaccinations. "Strap 'em, down, I say! Let's make it illegal" to not take the vaccine, Mr. Gates joked. Then he got serious again, citing failed attempts in the U.S. to enforce compulsory vaccinations.
In many respects, Mr. Gates remains a tech geek at heart. Aboard his plane, he expounded on an array of scientific topics: From developments in genotyping, to research showing that Bangladesh's high disease-immunity rates are due to "oral-fecal" transmission (when people ingest vaccines from contaminated water).
In Nigeria, Mr. Gates scored a diplomatic triumph. He won commitments from the sultan, and from Nigeria's governors, to take a more active role in polio vaccinations. "We really stand at the threshold of global health success on polio," he told the assembled governors at the close of the trip.
However, just three days later, a new front opened 2,000 miles away in Uganda. There, a woman walked into a hospital to say her son couldn't move his left leg. It was Uganda's first polio case in 12 years.
Cases also popped up in Mali, Togo and Ghana and Cote d'Ivore, which hadn't reported polio for four years. A girl in Kenya became that country's first polio case since 2006.
Polio, which spreads through water contaminated by human feces, paralyzes just one person for every 200 infected. Discovering just a few cases could mean that thousands have been infected. That demands massive vaccination campaigns.
On Feb. 28, 2009, Mr. Aylward, the WHO official, was grocery shopping in Geneva with his wife and son when he got an urgent email about the Uganda case. For 30 minutes, Mr. Aylward stood next to a spinach display, working his phone and setting in motion a plan that 10 days later vaccinated 48,000 children in Uganda.
Costly emergency responses like this became increasingly common last year. The Gates Foundation had set $47 million aside for emergencies, Mr. Aylward said. By early June, the money was running down.
That month, Mr. Gates flew to Geneva for the meeting in the WHO's underground room.
Mr. Aylward came with good news to offset the bad news about polio's resurgence, he recalled later. After describing the outbreaks, he shifted to Nigeria's progress against polio and described positive results from a trial of a new vaccine.
But those positives didn't offset the risks of polio's revival, say several attendees of a follow-up meeting. "It was becoming evident that the virus almost knew no bounds," said Dr. Steve Cochi, senior adviser at Centers for Disease Control. "It kind of confirmed some of our worst fears."
A month later in Seattle, Gates Foundation officials paused at a PowerPoint presentation showing the foundation's polio grants were approaching $1 billion. It was a staggering amount for a program that appeared to be stalling. "We can't go to Tachi and Bill and ask for more money," without reviewing the program, one person said, referring to Mr. Gates and Tachi Yamada, a top foundation official, according to an attendee.
In August, experts commissioned by the WHO landed in Angola, Pakistan, Afghanistan, India and Nigeria to evaluate the polio program. In Africa, a team found that once polio had been ended in some countries, weak health-care systems let it return. In northern India, bad sanitation, malnutrition and other intestinal issues are believed to hurt the oral polio vaccine's effectiveness.
These findings echoed the message to Mr. Gates in Nigeria, and marked a turning point among the Gates Foundation and other backers of the polio fight in the debate over whether the strictly "vertical" polio strategy could succeed.
In October, the Gates Foundation summoned backers of the program, including Unicef, CDC and Rotary, to its Seattle headquarters for a major rethink. Two weeks later it called in independent experts for help. The outcome of those meetings will be reflected in the revamped plan coming next week. Polio backers say they are buoyed by reports of just 71 polio cases worldwide this year, vs. 328 in the year-earlier period.
If approved in May by member nations of the WHO, the new strategy will set ambitious goals for getting close to eradicating polio by the end of 2012. The plan bolsters the core "vertical" approach of polio program but also adds a "horizontal" strategy, including training for health workers on topics such as hygiene and sanitation.
Nigeria will be a key testing ground. The country has made strong progress against the disease since Mr. Gates's visit. But stopping polio there, and in at least one of the three other countries where it's deeply rooted, will be the main challenge in the next three years, Mr. Aylward says. Failure to achieve that goal will raise questions over whether the program continues, he says.
A big hurdle is money. The polio program is $1.4 billion short of the $2.6 billion it needs over next three years. The Gates Foundation will continue its polio grants, but says it can't make up the shortfall.
But funding is just one worry for Mr. Gates in his new career. He built his foundation on the promise of life-saving vaccines, reflecting his penchant toward finding technological solutions to problems. As polio shows, technology can be hampered by political, religious and societal obstacles in the countries where he's spending his money. He's still learning how to navigate through those forces.
In Nigeria last year, Mr. Gates sat on the lawn behind his hotel reflecting on that. Science can simplify the job, he said, but "the human piece is the ultimate test."
Write to Robert A. Guth at email@example.com
2), 3), 4) POLIO IN TAJIKISTAN
Notable features of this outbreak
- First cases in WHO's European region since regional certification
- Virological links to northern India
- explosive epidemic, with cases in older age groups.
- 87 percent OPV3 coverage before the outbreak
Daily updates at www.euro.who.int
The following was viewed on 30 April.
From the European regional office, WHO
Polio situation update from Tajikistan
29 April 2010
As of 28 April 2010, the health authorities in Tajikistan have reported 171 cases of acute flaccid paralysis (AFP) to WHO. Laboratory tests have confirmed wild poliovirus type 1 in 32 cases; classification is pending for the remaining 139. Out of 68 administrative territories in Tajikistan, 24 are affected. All cases have been reported from the south-west of the country. So far, 12 deaths have been registered: 10 in children (under 15 years of age) and 2 in adults. Genetic sequencing has determined that the poliovirus found in Tajikistan is most closely related to virus from Uttar Pradesh, India.
A WHO expert team has been in Tajikistan since 16 April 2010, investigating the outbreak and providing technical support to the Government, in partnership with the United Nations Children’s Fund (UNICEF) and the US Centers for Disease Control and Prevention (CDC). WHO keeps all WHO Member States informed about its epidemiological and clinical findings through channels established by the International Health Regulations (IHR). On 26 April, 4 million doses of monovalent oral polio vaccine (mOPV1), supplied and deployed by UNICEF, arrived in Tajikistan. According to current plans, 1 090 000 children under 6 years of age will be vaccinated in three rounds of immunization starting next week.
WHO’s technical assistance programme in Tajikistan has short- and medium-term goals. In the short term, WHO is conducting a comprehensive outbreak investigation to support authorities in strengthening AFP surveillance and active case finding, ensure appropriate clinical management of patients and coordinate the nationwide vaccination programme. In the medium term, WHO supports the Government in strengthening its health system, including AFP surveillance structures, immunization programmes and capacities for outbreak response. WHO will continue this support until the outbreak is brought under control and advanced surveillance and immunization programmes are put in place.
Prevention and preparedness in the neighbouring region
WHO is in close contact with governments of Kazakhstan, Kyrgyzstan, Turkmenistan and Uzbekistan about preparedness and response measures. In Uzbekistan, 23 AFP cases were reported from the beginning of the year to 28 April 2010. Four of these were reported in weeks 15 and 16 in regions near Tajikistan. With its partners, WHO will assist in managing a two-round national polio immunization campaign in Uzbekistan. The governments of Kazakhstan, Kyrgyzstan and Turkmenistan have formed task forces and strengthened surveillance, and are considering vaccination campaigns. The Government of Kyrgyzstan began a subnational polio immunization campaign this week in the areas bordering Tajikistan. In neighbouring Afghanistan, authorities will begin a nationwide campaign on 3 May 2010. WHO has begun a risk assessment to identify other Member States at high risk of polio importation.
Partnerships and emergency appeals
In preparing their response, the health ministries of Tajikistan and Uzbekistan are receiving support from WHO, UNICEF, US CDC, the International Federation of Red Cross and Red Crescent Societies and other members of the Global Polio Eradication Initiative. WHO and UNICEF are urgently seeking funds to support their work. Rotary International, US CDC, the US Agency for International Development (USAID), and the Department for International Development (DFID), United Kingdom have already pledged emergency funding to support WHO’s work on the ground and UNICEF’s vaccination and social mobilization activities. Over US$ 1.2 million was raised during the past week.
WHO recommendations for travel to Tajikistan remain the same as for any other polio-infected country – immunization or boosting of past immunization. No further actions or travel restrictions are recommended.
3) Outbreak of poliomyelitis in Tajikistan in 2010: risk for importation and impact on polio surveillance in Europe
Eurosurveillance, Volume 15, Issue 17, 29 April 2010
1. World Health Organization Country Office Tajikistan, Dushanbe, Tajikistan
2. World Health Organization Regional Office for Europe, Copenhagen, Denmark
3. Europe and European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
Citation style for this article: World Health Organization Country Office Tajikistan, WHO Regional Office for Europe, European Centre for Disease Prevention and Control. Outbreak of poliomyelitis in Tajikistan in 2010: risk for importation and impact on polio surveillance in Europe?. Euro Surveill. 2010;15(17):pii=19558. Available online: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19558
Date of submission: 27 April 2010
On 23 April 2010, the World Health Organisation announced the confirmation of wild poliovirus serotype 1 (WPV1) in seven samples from children with Acute Flaccid Paralysis in Tajikistan, in the context of a multi-district cluster starting in December 2009. As of 28 April, 32 of 171 reported cases were laboratory-confirmed and most closely related to virus from Uttar Pradesh, India. This outbreak demonstrates the high risk that still exists for importation of wild poliovirus into polio-free regions.
On 23 April 2010, the World Health Organisation announced the confirmation of wild poliovirus serotype 1 (WPV1) in seven samples obtained from children with Acute Flaccid Paralysis (AFP) detected in Tajikistan in the context of a multi-district AFP cluster staring in December 2009.
Poliomyelitis (polio) was eliminated in the WHO European Region and the Region was certified polio-free in 2002. Since then, considerable efforts of national authorities and of the international public health community have sustained the polio-free status for the 880 million population of the Region. The last indigenous case of wild poliovirus infection in the WHO European Region was reported in Turkey in 1998 . However, poliovirus imported from polio endemic countries remains a threat. In 1996, following migration resulting from the opening of borders in 1992, Albania reported 138 laboratory confirmed cases of WPV1 infection, including 16 deaths, with 24 confirmed polio cases detected in the bordering United Nations administered Province of Kosovo . The main age group affected was the group of 10 to 34 years-old which accounted for 79% of cases and the lowest incidence was reported among children aged one to nine years. Among those with known vaccination status, 93% had received at least three doses of oral polio vaccine (OPV). The last outbreak in the EU, due to imported WPV3, occurred in the Netherlands in 1992 and 1993 in a community objecting to vaccination . A total of 71 individuals were paralysed and two deaths were reported. The last cases of imported wild poliovirus in the WHO European Region were reported in 2001. These occurrences were associated with WPV1 originating from India, with three Roma children in Bulgaria and one non-paralytic case in Georgia . These cases related to importation did not result in indigenous transmission, defined by the WHO as uninterrupted transmission occurring for more than 12 months.
Tajikistan, with a 6.6 million population, is one of the five Central Asian Republics and borders Uzbekistan, Kyrgyzstan, China and Afghanistan. Two outbreaks of polio were registered in Tajikistan in the 1990s, with 111 and 26 cases of poliomyelitis reported to the WHO in 1991 and 1994, respectively . The last clinically confirmed case of poliomyelitis observed in Tajikistan was in 1997 [1,6].
The reported vaccine coverage with three doses of OPV in Tajikistan in 2008 was 87% , which is below the WHO target of over 90% . In 2007, the national health authorities in Tajikistan conducted an immunisation campaign against polio, targeting children less than three years old in the areas bordering Afghanistan.
At the beginning of April 2010, the WHO Country Office in Tajikistan was informed of an increase in AFP cases in multiple contiguous districts. On average, Tajikistan reports 35-40 AFP cases annually with peaks in July and October. As of 28 April, the Ministry of Health of Tajikistan reported 171 AFP cases to WHO, with a sharp increase in the past two weeks, including 12 deaths and 32 cases of laboratory confirmed WPV1 infection; the tests were conducted at the WHO regional reference laboratory for polio, based at the Chumakov Institute of Poliomyelitis and Viral Encephalitis, Moscow, Russian Federation . Genetic sequencing has determined that the poliovirus is most closely related to virus from Uttar Pradesh, India. One-hundred and thirty-six (80%) of the AFP cases were in children aged under five years (age range 0-17 years). Cases were mainly reported from districts bordering Afghanistan and Uzbekistan. The Uzbek national authorities are investigating three cases of AFP.
Following the confirmation of WPV1 in Tajikistan, three rounds of nationwide immunisation with monovalent OPV type 1 are planned for all children aged five years or younger (1.1 million children) with a two week interval between each round, starting the first round on 4 May. In addition, there are ongoing efforts to strengthen AFP surveillance. Upon the request of the Ministry of Health of Tajikistan, WHO deployed a multi-disciplinary team of clinical, epidemiological, and virological experts, to investigate the event and assist national authorities in planning and implementing the necessary public health measures. WPV1 and WPV3 activity is currently recorded in Afghanistan. As of 20 April, Afghanistan reported eight cases of poliomyelitis (one WPV1 and seven WPV3) for the year 2010. The onset of disease in the most recent case was on 8 April. Since 2002, no cases of wild poliovirus infection have been detected in northern Afghanistan, areas with recognised high quality AFP surveillance. Pakistan reported 13 cases of polio due to WPV1 and WPV3 so far in 2010 . Polio is still endemic in four countries worldwide; besides Afghanistan and Pakistan these are India and Nigeria .
The movement of Tajik nationals in the European Union (EU) is limited as less than 2,200 Schengen visas were issued in 2009. Considering these small numbers of Tajik nationals coming to the Schengen area, the risk of spread of WPV1 associated with the ongoing outbreak in Tajikistan within the EU is considered to be limited. However, importation of cases cannot be excluded, and high levels of vaccine coverage with three doses of polio vaccine are needed to ensure that importation into the EU will not occur. Pockets of susceptible populations do exist in the EU and the risk of disease in these groups is high if the virus is introduced in these communities. Avoiding complacency and maintaining good AFP and/or enterovirus surveillance in the EU to comply with WHO targets is of utmost importance to prevent WPV importation and further spread, particularly considering that 90% of cases associated with WPV infection do not have clinical symptoms. The need to maintain vigilance, implement adequate measures to detect and prevent re-importation of polio into polio-free regions is also stressed in a paper by H Nokleby et al. in this issue of Eurosurveillance .
While AFP surveillance is considered the gold standard for certification purposes, other surveillance strategies and sources of data have been accepted by the WHO European Regional Certification Commission of the Eradication of Poliomyelitis that enable the detection, rapid reporting, and investigation of any paralytic polio cases. This applies to countries that have been non-endemic for a long time, with high levels of sanitation and strong health systems. Accepted alternative surveillance strategies include enterovirus surveillance and/or environmental surveillance for polioviruses. Member states of the WHO European Region conduct a combination of AFP, enterovirus, and/or environmental surveillance. Forty-three of the 53 member states in the WHO European Region conduct AFP surveillance, including 23 of the 29 EU/EEA countries (Liechtenstein is not reporting to WHO), 41 have implemented enhanced enterovirus surveillance while seven are doing environmental surveillance through sewage systems.
A region is certified as polio-free if no indigenous poliomyelitis cases are identified for a period of more than three years in the presence of high quality, certification-standard surveillance. The current outbreak in Tajikistan represents the first introduction of wild poliovirus in the WHO European Region since it has been certified polio-free in 2002. Therefore, strong measures are needed to protect the status. The present situation calls for strong political and financial commitment from all member states to ensure the WHO European Region sustains its polio-free status and that global eradication of polio will be reached by 2012.
Although the Region is considered at high-risk for importation of wild poliovirus due to ongoing global travel, trade, and migration, especially with the four polio endemic countries, the current poliomyelitis outbreak in Tajikistan does not substantially affect the risk for further spread to the EU Member States at this time. It is important to note that WHO does not recommend restrictions on international travel and trade in case of the detection of wild poliovirus but emphasizes that standard recommendations regarding vaccination of travellers to and from a polio-affected country apply until a polio outbreak is interrupted.
The authors acknowledge the Ministry of Health of Tajikistan for actions taken in response to the ongoing polio outbreak and for cooperation with the Global Polio Eradication Initiative.
1. Certification of Poliomyelitis Eradication: European Region declared ‘polio-free’. Fifteenth meeting of the European Regional Certification Commission. Copenhagen, 19-21 June 2002, p 103. Available from: http://www.euro.who.int/document/E88105.pdf
2. Ciofi degli Atti M, Prevots R, Sallabanda A, Malfait P, Diamanti E, Aylward B, et al. Polio outbreak in Albania 1996. Euro Surveill. 1997;2(5). pii=162. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=162
3. Oostvogel PM, van Wijngaarden JK, van der Avoort HG, Mulders MN, Conyn-van Spaendonck MA, Rümke HC, et al. Poliomyelitis outbreak in an unvaccinated community in the Netherlands, 1992-3. Lancet. 1994;344(8923):665-70.
4. Noah N, Ramsay M, Twisselmann B. Imported cases of polio in Bulgaria – vaccination campaign postponed. Euro Surveill. 2001;5(21). pii=1747. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=1747
5. World Health Organization Regional Office for Europe. The centralized information system for infectious diseases (CISID). Available from: http://data.euro.who.int/cisid/?TabID=239415
6. Poliomyelitis. Fact sheet 04/02. Copenhagen, 21 June 2002. WHO, Rotary International, CDC, Unicef. Available from: http://www.euro.who.int/document/mediacentre/epolfreeeuro.pdf
7. World Health Organization. Tajikistan reported immunization coverage, 1980-2008. Available from: http://www.who.int/immunization_monitoring/en/globalsummary/timeseries/tscoveragebycountry.cfm?C=TJK
8. Global polio eradication initiative. Programme of Work 2009 and financial resource requirements 2009-2013, as of May 2009. WHO, Rotary International, CDC, Unicef. Available from: http://www.polioeradication.org/content/general/Final_English.GPEIProgrammeofWork2009.pdf
9. Global polio eradication initiative . Polio in Tajikistan, first importation since Europe certified polio-free. WHO, Rotary International, CDC, Unicef. 22 April 2010. Available from: http://www.polioeradication.org/content/general/LatestNews201004.asp#03
10. Nokleby H, de Carvalho Gomes H, Johansen K, Kreidl P. Protection against poliomyelitis in Europe. Euro Surveill. 2010;15(17). pii=19556. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19556
Eurosurveillance, Volume 15, Issue 17, 29 April 2010
4) Protection against poliomyelitis in Europe
1. European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
Citation style for this article: Nokleby H, De Carvalho Gomes H, Johansen K, Kreidl P. Protection against poliomyelitis in Europe. Euro Surveill. 2010;15(17):pii=19556. Available online: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19556
Date of submission: 27 April 2010
The reappearance of circulating wild poliovirus type 1 (WPV 1) in Tajikistan is the first outbreak from imported wild poliovirus since the World Health Organization (WHO) European Region was declared polio-free in 2002. The risk of poliomyelitis importation to the European Union and European Economic Area countries has probably not increased, but the current outbreak is a reminder that high vaccination coverage, monitoring of protective immunity and maintaining surveillance are important to sustain the present polio-free situation.
Poliomyelitis (polio) is an acute, communicable disease caused by one of three wild-type poliovirus serotypes (WPV types 1-3), or by vaccine associated paralytic polio (VAPP) caused by the live, oral vaccine (OPV). It is characterised by symptoms of varying degree of severity, from subclinical or non-specific disease to rapid onset of acute flaccid paralysis (AFP). The polioviruses are spread mostly by the faecal – oral route. Before vaccination was introduced, most children were exposed to wild-type poliovirus. Of the persons infected, 1:100 to 1:1,000 develop paralytic polio, depending on age, and with the lowest incidence in the very young. It has been discussed that a genetic factor in the host could play a role in why only some individuals develop paralytic poliomyelitis .
The first polio vaccine, an inactivated polio vaccine (IPV), became available in 1955. The number of polio cases decreased rapidly in countries introducing the vaccine. Trivalent live attenuated oral polio vaccine (OPV) was launched in 1963. The OPV elicits mucosal immunity, which makes it more efficient in stopping the spread of virus than IPV. The OPV is also easier to apply as no injections are needed, and the need for educated healthcare personnel is limited. The Global Polio Eradication Initiative (GPEI) was launched by World Health Organization (WHO) in 1988, with the goal of eradicating polio before the year 2000 . The GPEI was based on the availability and use of OPV, making large immunisation campaigns in countries with limited financial and healthcare resources possible, even though the need to maintain an adequate cold chain to avoid potency loss has been a challenge in many countries.
Use of OPV contains a small risk of polio-like disease caused by one of the three Sabin vaccine-related poliovirus serotypes; vaccine associated paralytic polio (VAPP). VAPP is seen after about one of one million vaccinations, most often in immunocompromised individuals. Through replication and spread in a susceptible population, the vaccine virus may gradually change into a vaccine-derived poliovirus (VDPV) and regain virulence (Table 1). Outbreaks caused by circulating vaccine-derived virus have been reported from several countries worldwide, with eg 153 paralytic cases reported from Nigeria (VDPV2) in 2009 . To avoid this risk most European countries now use only IPV in their vaccination programs .
Table 1. Polioviruses that cause paralytic disease
The Global Polio Eradication Initiative
The GPEI has had an enormous impact on the number of polio cases in the world. The total number of cases decreased from an estimated 350,000 in 1988 to less than 2,000 cases in 2009, and the number of polio endemic countries from 125 to four. The criteria for declaring a single country or a whole WHO region polio-free include reporting of zero indigenous polio cases for at least three years, and a documented surveillance system good enough to discover potential cases. The WHO Region of the Americas was declared polio-free in 1994, the Western Pacific Region in 2000 and the European Region in 2002 .
In spite of the large decrease in the number of polio cases the goal of global eradication has been difficult to reach. Wild poliovirus type 2 has not been detected since 1999, but types 1 and 3 are both circulating, and are still endemic in Pakistan, Afghanistan, Nigeria, and India. In the first three countries the main problem has been lack of immunisation, due to local vaccination opposition as in the case of Nigeria  or immunisation problems in areas of conflict. In India outbreaks with poliovirus 1 and 3 have continued in spite of very high vaccination coverage. The most probable explanation in India is that the OPV has not been sufficiently immunogenic in some population groups. Monovalent type 1 and 3 polio vaccines provide better immunogenicity , and in 2009 an almost as immunogenic bivalent vaccine against types 1 and 3 was introduced (Table 2). The number of cases and affected areas in India has recently been reduced due to these efforts.
Table 2. Vaccines against poliomyelitis
Imported infections from the four still endemic countries have been observed in many parts of the world, and in Africa virus circulation has been re-established in some countries that have been polio-free for many years, mostly due to importation from Nigeria since polio again became endemic there in 2003 . However, the general situation has improved recently, with only 71 notified cases in 2010 compared with 328 cases at the same time in 2009 .
The current outbreak in Tajikistan - an important reminder for the European Union (EU)/European Economic Area (EEA)
The present outbreak of polio from a polio serotype 1 virus in Tajikistan is described in another article in this issue of Eurosurveillance . For the EU/ EEA countries this outbreak does probably not change the current risk of polio importation, as there is already much travel between the four large polio-endemic countries and the EU/EEA. However, the situation in Tajikistan is a reminder that importation of poliovirus to polio-free regions may happen at any time as long as polio virus is circulating in the world. In many European countries there may be population pockets with lower vaccination coverage, where introduction of poliovirus can lead to reestablishment of virus circulation. Earlier outbreaks, such as in the Netherlands in 1992, have shown that this may happen, even in countries with high general vaccination coverage .
Polio surveillance has several elements, AFP surveillance being one of them. Enhanced enterovirus surveillance is accepted by WHO as an alternative in countries that have been polio-free for years. Moreover, measuring of vaccination coverage and monitoring of protective immunity in the population are tools for controlling whether immunisation efforts lead to the expected result. Another element is checking for poliovirus in the environment, usually done in the form of sewage sampling. Checking defined sewage systems for wild or vaccine-derived poliovirus is performed routinely in seven EU countries and helps to quantify the current risk of virus importation in each country.
The change from OPV to IPV reduces the risk of disease caused by VPDV. WHO still considers use of OPV necessary to control polio in countries where the disease is still endemic or circulation is re-established. Regardless of that, several Indian paediatricians have advocated IPV also in India and trials are currently underway in less privileged populations . Encouraging countries to change to IPV when possible will reduce the risk for VAPP for everybody.
High vaccination coverage in all parts of the population is the most important part of polio protection in Europe. Good surveillance, including enhanced enterovirus or AFP surveillance, vaccination coverage and population immunity, will help us discover weaknesses in the system or eventual importation of poliovirus, and make us able to implement the necessary measures to avoid re-establishment of polio circulation in a timely manner.
As long as poliovirus is circulating anywhere in the world it may easily be imported to polio-free regions. High vaccination coverage, including booster doses of IPV for persons travelling to polio endemic countries, and enhanced surveillance to detect imported cases early is necessary to avoid re-established circulation in other countries.
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