As the vaccination campaign to eliminate polio nears its goal, researchers say that developing drugs could be essential to ensure the disease does not reappear after vaccination ends.
In a report published last week (10 March) by the National Research Council of the US National Academies, they warn that stopping vaccination could be complicated and risky.
The oral polio vaccine contains a live but weakened form of the virus that protects people from infection and can spread from person to person, immunising the more of the population as it does.
While this increases the effect of a vaccination campaign, it also means the virus could mutate and regain its ability to cause disease, to which an unvaccinated population would be vulnerable.
The report concludes that if the oral polio vaccine is discontinued "it would be extremely useful and possibly essential to develop another tool to control outbreaks of polio". It suggests that drugs be used in combination with a non-live polio vaccine.
Bruce Aylward, global coordinator of the World Health Organization's (WHO) Polio Eradication Initiative, says one of the report's most important findings is that it identified several new targets for a potential polio drug.
The committee recommends that at least one, and preferably two drugs be stockpiled along with a vaccine, so that any future outbreaks of poliovirus can be contained.
They acknowledge, however, that obtaining funding for drug development will be difficult.
Adam Finn, head of the Child Health Unit at the University of Bristol, United Kingdom says that encouraging either public or private investment in creating new polio drugs would be a "unique challenge”, since the drug would be for a disease that no longer exists.
The WHO's polio eradication began in 1988, when the disease was causing 350,000 cases of paralytic disease in 125 countries each year. By 2003, there were just 784 cases in six countries.
The WHO plans to stop using the oral polio vaccine three years after transmission of the virus between people is documented for the last time.
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