UK health authorities will offer children under 10 living in London an additional dose of polio vaccine amid rising concern about a comeback of the disease.
While nobody has tested positive for being infected with the type of polio virus that can cause paralysis, authorities have nonetheless found it on several occasions in London sewage samplings, officials said in a statement Wednesday.
The UK’s vaccine expert advisory committee recommended offering the extra polio booster to kids after scrutinizing months worth of sewage surveillance data and considering London’s polio vaccination coverage, which is lagging behind World Health Organization targets.
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Of the 116 polio viruses isolated from London sewage samples in recent months, the vast majority are relatively harmless versions classified as “vaccine-like” virus. People can spread this version through their feces after receiving a live-attenuated oral version of polio vaccine that’s no longer offered in the UK.
If this version of the virus undergoes enough mutations, however, it sometimes becomes a more dangerous form of the virus that can once again cause paralysis on rare occasions.
On several occasions in London, this type of more dangerous polio virus has been detected in sewage samples. This is known as “vaccine-derived” polio virus.
The goal of the booster program is to both strengthen protection against paralysis in London and to slow down transmission, officials said.
People can often transmit the polio virus without showing any symptoms.
The UK’s last case of wild polio was in 1984 and the country was declared polio-free in 2003.