The World Health Organization on Nov. 13, 2020, granted Emergency Use Listing to a novel oral polio vaccine, developed by the Bill & Melinda Gates Foundation. The vaccine is designed to treat type 2 vaccine-derived poliovirus — the same type of polio identified in the U.K.’s first polio outbreak in 40 years.
Health officials in the U.K. this month identified the country’s first polio outbreak in 40 years, and believe the outbreak was caused by a strain of polio found in the oral polio vaccine.
Health officials in Britain warned parents on June 22 to ensure their children have been vaccinated against polio after multiple closely related versions of the virus that cause the disease were found in sewage water at the London Beckton Sewage Treatment Works — the largest water treatment plant in the U.K.
“The Global Polio Laboratory Network has confirmed the isolation of type 2 vaccine-derived poliovirus (VDPV2) from environmental samples in London, United Kingdom, which were detected as part of ongoing disease surveillance,” the World Health Organization (WHO) states on its website.
The U.K. Health Security Agency (UKHSA) said it believes the virus was “vaccine-derived,” meaning it came from someone who received the live polio vaccine. That person then passed the virus to individuals in London, who shed the virus into their feces.
The viruses’ genetic sequences suggest “there has been some spread between closely linked individuals in north and east London,” the UKHSA said.
The virus was isolated from environmental samples collected between February and May, and no related cases of paralysis have been detected, the WHO said. “Additional sewage samples collected upstream from the main waste-water treatment plant’s inlet are being analyzed.”
People vaccinated with the live oral polio vaccine (OPV) shed traces of the virus in their stool — which eventually end up in sewage wastewater, NPR reported. Scientists believe a person brought the virus into London and then spread it to others who were unvaccinated.