LONDON — Children ages 1-9 in London were made eligible for booster doses of a polio vaccine Wednesday after British health authorities reported finding evidence the virus has spread in multiple areas of the city but found no cases of the paralytic disease in people.
Britain’s Health Security Agency said it detected viruses derived from the oral polio vaccine in the sewage water of eight London boroughs. The agency’s analysis of the virus samples suggested “transmission has gone beyond a close network of a few individuals.”
The agency said it had not located anyone infected with the virus and that the risk to the wider population was low. The decision to offer young children boosters was a precaution, it said.
“This will ensure a high level of protection from paralysis and help reduce further spread,” the agency said.
The agency said it is also expanding surveillance of sewage water to at least another 25 sites in London and nationally.
Most people across Britain are vaccinated against polio in childhood. According to the World Health Organization, only one in 200 polio infections leads to paralysis; most people don’t show any symptoms.