Guest essay by Eric Worrall
There is no doubt Polio vaccines have been an overwhelming benefit for humanity. Extensive use of Polio vaccines has led to the near eradication of this dreadful disease. But Polio is a live vaccine, a weakened version of the real virus. Sometimes live vaccines go horribly wrong.
Vaccine-derived polio spreads in Africa after defeat of wild virus
Fresh cases of disease linked to oral vaccine seen in Sudan, following outbreak in Chad
A new polio outbreak in Sudan has been linked to the oral polio vaccine that uses a weakened form of the virus.
News of the outbreak comes a week after the World Health Organization (WHO) announced that wild polio had been eradicated in Africa.
When a child receives the oral vaccine, the weakened virus replicates in the intestine, encouraging the production of antibodies, and can be present in excreta. In an area where there are high enough levels of immunity in the population, this usually does not present a problem, even if sanitation is poor.
But in areas where there is both poor sanitation and a lack of general immunisation the virus can survive and circulate for months, mutating over time until it poses the same risk of paralysis-causing disease as wild polio.
…Read more: https://www.theguardian.com/global-development/2020/sep/02/vaccine-derived-polio-spreads-in-africa-after-defeat-of-wild-virus
A statement from the WHO is available here.
It is far from clear exactly how local health authorities and visiting medical teams lost control of the vaccine. Hopefully a review of this outbreak will improve future outcomes.