Polio is back:

The UK Health Security Agency said that, since early February, 116 polioviruses had been identified in 19 sewage samples from boroughs in north-east and central London including Barnet, Camden, Hackney, Haringey, Islington and Waltham Forest.

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While a small number of polioviruses are detected in sewage in the UK each year, the large number detected over recent months is unusual, and appears to reflect transmission of the virus in the community.

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Public health experts said it appeared such transmission was asymptomatic, and was likely to have been caused by an individual recently vaccinated with live oral polio vaccine (OPV) entering the UK. OPV generates excellent gut immunity against polio; however, people who have been recently vaccinated can shed vaccine-like virus in their faeces.

While this weakened form of the virus does not cause illness, the concern is that if it circulates it can gain mutations that increase its virulence, resulting in vaccine-derived poliovirus – which has the potential, albeit rare, to cause paralysis in those who are unvaccinated.

Kids 1 through 9 should get a booster.