ON JUNE 8th reports of a suspected case of polio came from Venezuela. Fortunately, it turned out to be a false alarm. The report that came from Papua New Guinea on June 22nd, though, is no fiction. It was issued by the World Health Organisation and concerns not one, but three children who have tested positive for a threatening polio virus.
Around the world, polio is in full retreat. A mere three countries are still known to harbour wild polio viruses. These are Afghanistan, Nigeria and Pakistan. In 2017 only 22 cases of polio caused by such wild viruses came to the attention of the authorities. Unfortunately, the reason for this success, which is the extensive vaccination against polio of children throughout the world, can occasionally backfire and itself cause polio outbreaks.
In many countries polio vaccine includes live, attenuated viruses which breed in the recipient’s intestines and then enter the bloodstream, thereby triggering a protective immune response. An...Continue reading
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