More polio cases now caused by vaccine than by wild virus

Four African countries have reported new cases of polio linked to oral vaccine, as global health numbers show re are w more children being paralyzed by viruses originating in vaccines than in wild. In a report late last week, World Health Organization and partners ted nine new polio cases caused by vaccine in Nigeria, Congo, Central African Republic and Angola. Seven countries elsewhere in Africa have similar outbreaks and cases have been reported in Asia, including two countries where polio remains endemic, Afghanistan and Pakistan.

In rare cases, live virus in oral polio vaccine can mutate into a form capable of sparking new outbreaks. All current vaccine-derived polio cases have been sparked by a 2 virus contained in vaccine. 2 wild virus was eliminated years ago.

Polio is a highly infectious disease that spres in contaminated water or food and usually strikes children under 5. About one in 200 infections results in paralysis. Among those, a small percent die when ir breathing muscles are crippled.

Dors last week pledged $2.6 billion to combat polio as part of an erication initiative that began in 1988 and hoped to wipe out polio by 2000. Since n, numerous such delines have been missed.

To ericate polio, more than 95% of a population needs to be immunized. WHO and partners have long relied on oral polio vaccines because y are cheap and can be easily ministered, requiring only two drops per dose. Western countries use a more expensive injectable polio vaccine that contains an inactivated virus incapable of causing polio.

Independent Monitoring Board, a group set up by WHO to assess polio erication, warned in a report this month that vaccine-derived poliovirus is “spreing uncontrolled in West Africa, bursting geographical boundaries and raising fundamental questions and challenges for whole erication process.”

group ted that officials were alrey “failing bly” to meet a recently approved polio goal of stopping all vaccine-derived outbreaks within 120 days of detection. It described attitude of WHO and its partners to stopping such vaccine-linked polio cases as “relaxed” and said “new thinking” on how to tackle problem was needed.