Poliovirus has been found in samples of sewage in London, England. Health experts said the virus most likely came from someone who had received a live polio vaccine overseas.
They also said they find the virus in sewage samples from time to time, but this is the first time that a cluster of genetically-linked samples has been found repeatedly over a period of months.
While the live virus vaccine hasn’t been administered in England since 2004, many other countries still use the wild virus version — which also can cause vaccine-derived polio in some people who receive it or are exposed to it. Globally, there were 959 cases of vaccine-derived polio in 2020; the vaccine-derived virus is the only poliovirus currently circulating in Africa.
SOURCES:
BBC June 22, 1950
Global Polio Eradication Initiative