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Print version ISSN 0042-9686
Bull World Health Organ vol.81 n.9 Genebra Sep. 2003
Polio eradication: 7 countries and US$ 210 million to go
The World Health Organization launched a final push on 29 July to eradicate polio by 2005 with a call to donors for an additional US$ 210 million to finally stamp out the incurable laming disease that mainly affects under-five-year-olds. WHOs Director-General Jong-Wook Lee has appointed David Heymann as his representative on polio eradication following the infectious diseases experts success heading a WHO team that helped stop the spread of SARS earlier this year.
When WHO first launched its eradication drive in 1988, polio was present in over 125 countries. Since then, the number has been reduced to seven. The original target date of 2000 to eradicate polio was missed but WHO officials are confident that with sufficient funding and political leadership eradication can be achieved in the next 18 months. Between August and December of this year as many as 175 million children will be vaccinated in India, Nigeria and Pakistan which account for 99% of new cases, as well as in Afghanistan, Egypt, Niger and Somalia.
"Donors have already invested $3 billion in the programme and we're now in the end game for stopping transmission globally," said Dr Heymann. "But money is not infinite, so we have to make sure it works before other priorities take over".
In addition to these seven countries, neighbouring ones at highest risk of imported cases, as well as others with low routine vaccination coverage, will carry out mass immunization campaigns.
In January, a child was paralysed by polio in Lebanon for the first time in ten years. Genetic sequencing showed that the virus had been imported from India. Polio campaigns to prevent or limit the spread of imported polioviruses since 2000 have cost well over US$ 100 million.
Dr Heymann said that in the past 12 months, polioviruses had also spread from Nigeria to nearby countries, including Ghana and Burkina Faso, which had recently become polio-free.
"Efforts to completely stamp out the disease have been hampered by insufficient funding from the international community and insufficient government commitment at the sub-national level," he said. "Difficulty in reaching and engaging minority populations have also hindered efforts". For example, Moslem clerics in Nigerias Kano State, where polio is most prevalent in that country, had been receiving false information that polio vaccines had birth-control and other untoward effects. This severely limited their ability to advocate the programme effectively in communities. By contrast, most conflict-affected countries, such as Angola which once had thousands of cases a year, are now polio-free.
The main vaccine used in the eradication programme, known as oral polio vaccine, is inexpensive at less than 10 US cents per dose, but substantial funds are still needed to finance distribution, disease surveillance and other activities such as vaccinator training and social mobilization. Following commitments by G8 leaders at their two most recent summits, in Kananaskis and Evian, to fill the polio funding gap, Canada, Japan, Russia and the United Kingdom have pledged new funding.
Scientists say polio, like smallpox which was declared eradicated in 1980, is one of the few diseases that can be stamped out because the poliovirus only affects humans, has no animal reservoir and cannot survive long in the environment. Also, oral polio vaccine is effective, inexpensive and gives long-lasting immunity.
In theory, the poliovirus will become extinct if deprived of its human host through immunization. If all goes to plan, populations in vulnerable countries will be immunized with oral polio vaccine and receive additional doses during National Immunization Days and mop-up campaigns by the end of 2004.
At the same time, the Global Polio Eradication Initiative is minimizing the risk of re-occurrence by working with countries to identify and inventory all stocks of wild poliovirus so that they can, within one year of interruption of virus transmission, be placed under P3 biosecurity conditions, the second-to-top security level. Smallpox is now stored at P4 maximum security; decisions on the final level of biosecurity needed for polio viruses will be taken as decisions on long-term routine polio immunization are finalized.
Dr Heymann said bio-terrorists were unlikely to resort to polio stocks for myriad reasons, including the fact that the disease only causes paralysis in 1 of 200 people infected. As the world prepares for the post-certification era (the period after global certification, which could occur as early as 2008) there will need to be an international consensus on whether to continue routine immunization with the oral poliovirus vaccine. Such decisions will be taken only after carefully balancing the risks associated with the options available. These must also bear in mind the small potential risk of an inadvertent release of wild poliovirus from labs that are storing the virus or from vaccine manufacturers who must produce their vaccines from live poliovirus strains. Ultimately, individual countries will decide their future immunization policy, based on such considerations.