After 18 years, the campaign to eradicate polio is still striving to dislodge the disease from its last few strongholds in the developing world.
Now a group of long-term supporters led by Isao Arita of the Japanese Agency for Cooperation in International Health are questioning the wisdom of this approach. Writing this week in Science, they say polio might never be wiped out, and that attention should instead be turned to effective control.
In this article Leslie Roberts outlines the campaign's problems and why the critics have called for a reassessment.
Evidence suggests that poliovirus can circulate undetected longer than previously thought making prospects for eradication "very grim indeed", say the sceptics. In Sudan last year a strain of polio was found that had been undetected for five years — while the country was labelled polio-free.
Another problem in countries such as Angola, Afghanistan and the Congo is ongoing conflict, which is thwarting efforts to eliminate the virus.
Even where efforts are achieving the highest vaccination rates ever, as in India, poverty means polio is still hanging on. This could be because children are infected with other viruses that compete with the vaccine in the gut. Chronic diarrhoea could also contribute by washing the vaccine out of the body.
The cost of the eradication campaign is skyrocketing — doubling to US$700 million between 2000 and 2005. Critics argue that the money would be better spent increasing routine immunisation against all vaccine-preventable diseases.Link to full article by Isao Arita et al. in Science