Polio remains a dogged foe to WHO efforts to eradicate

October 3, 2005 2:05 PM

"It was a terrible time." (bugmenot) "50 years ago, Rhode Island suffered through its last -- and worst -- polio epidemic." [more inside]
posted by paulsc (2 comments total)

Despite the availability for decades of generally effective vaccines, and a well understood pathology [link to .pdf file] which does not include a wild reservoir vector, and a worldwide program to eradicate the disease underway since 1988, this year has witnessed the spread of the disease back into areas which were once free of it. Do the problems with the polio eradication effort tell us anything about vaccination as a strategy for managing epidemic disease?

As the September 2005 report from the World Health Organization's Global Polio Eradication Initiative observes, "There are now more polio cases in re-infected countries than in endemic ones: for the first time ever, in 2005, the number of cases in the re-infected countries is higher than in the endemic countries (749 cases versus 470 cases respectively)." In a June, 2004 story on the outbreak of polio to other countries from Nigeria, the Washington Post noted thatOnly about 1 in every 200 polio cases results in the limb weakness or paralysis that allow physicians and nurses to recognize the disease. Consequently, finding a dozen cases implies that at least a thousand people are harboring, and possibly transmitting, the virus."

As outbreaks in Yemen and Indonesia this year have demonstrated, polio is able to rapidly capitalize on lapses in the rate of vaccination in countries where the populace becomes complacent. And in the past, even vaccination programs with the commonly distributed oral vaccines have proven to be sources of new cases. In 2002, a strain of polio virus used in the manufacture of oral vaccine spontaneously redeveloped virulence (an ability to cause person-to-person infection), causing an outbreak in Haiti and the Domincan Republic. Conjectures that HIV was caused by manufacture of a polio vaccine was previously discussed on MeFi here, and similar reports may have supported the promouncements of Muslim clerics in 2003, which seem to have led to the outbreaks this summer.
posted by paulsc at 2:07 PM on October 3, 2005

Do the problems with the polio eradication effort tell us anything about vaccination as a strategy for managing epidemic disease?

No. According to the article you linked to,

This reflects both tremendous progress in endemic countries and the great vulnerability of polio-free countries where low routine immunization coverage puts children at risk.

The sum total of 2005 cases is below 1300, across the entire globe. In 1988, there were 350,000 cases of polio.

Eradication efforts have reduced the incidence of polio by 99% inside of 20 years.

The WaPo article you link to shows that the greatest increase in polio is in regions beset by strife such as most of Sudan, where vaccination and other public health initiatives have virtually ceased. I'm also unsure whether vaccination in a country such as Yemen was all that good to begin with.

I think the $3 billion effort has been money well spent. Countless lives have been saved, or spared the agony and complications of survival. We are, however, in the most difficult phase. The last 1% may prove as costly and difficult at least as the prior 10%. Polio isn't like Ebola or SARS -- you don't know you have it within days or weeks of infection. Many of the cases that are being found in previously "clear" countries may well have been infected before that declaration.

Finally, your own suggestion that propaganda and suspicion against vaccination programs has led directly to increased incidence would seem, again, to support the idea that vaccination works, when it's allowed to (and given time).

If you were going to undercut your own arguments, why did you post? Wouldn't it be better to post without gratuitous leading questions?
posted by dhartung at 7:51 PM on October 3, 2005