Clinics in the UK have been put on high alert after a disturbing find in London's sewers. Authorities say multiple closely related samples of the virus that causes polio have been found in sewage water, suggesting there is an outbreak occurring in the capital, NPR reports. "The last case of wild polio contracted in the UK was confirmed in 1984" and the country was officially declared polio-free in 2003, but people are now being urged to check whether they are up to date with vaccines, the British government said in a press release.
Polio is transmitted through the fecal-oral route, with people sometimes becoming infected when somebody who hasn't washed their hands properly handles food. Researchers say the samples detected are "vaccine-derived" and they believe the outbreak may have started with somebody who received the live oral polio vaccine overseas and then traveled to Britain, which stopped using the live vaccine in 2004, the BBC reports. British authorities say there have been no actual cases of polio reported. In rare cases, the virus can cause paralysis in people who haven't been fully immunized, though most infected people never show symptoms.
Health authorities say the risk to the public seems to be low, although other countries have seen a rise in polio cases after the pandemic disrupted childhood vaccination programs. Polio researcher Angela Rasmussen at the University of Saskatchewan tells NPR that the outbreak is likely very small and "could be within an extended family." "My biggest concern is the fact that there is a larger population now that hasn't been vaccinated on schedule," she says. "I think that applies everywhere." (Read more polio stories.)