Polio vaccine boosters are offered to London children as the virus spreads

A health worker gives a polio vaccine to a child in Karachi, Pakistan, on May 23. British health authorities on Wednesday said they will offer a polio booster dose to children aged 1 to 9 in London, after finding evidence the virus has been spreading in multiple regions of the capital. (Fareed Khan/AP)

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."