U.K. Clarifies Response to Poliovirus Detections in London Sewage
The World Health Organization (WHO) has formally confirmed that the U.K. has a ‘circulating’ vaccine-derived poliovirus type 2 (VDPV2) based on detecting the same isolate for more than 60 days.
And evidence that the virus detected in London is genetically linked to the poliovirus detected in Israel and the U.S.
An average of 1 to 3 poliovirus isolates per year have been detected from U.K. sewage samples in recent years.
However, these have all been single detections that are unrelated to each other.
In this instance, the isolates identified are genetically related, which has prompted the need to investigate the extent of transmission of this virus in Northeast London.
The most likely scenario is that a recently vaccinated individual entered the U.K. before February 2022 from a country where the oral polio vaccine (OPV) has been used for supplementary immunization campaigns.
The UKHSA confirmed on November 14, 2022, the environmental surveillance had been expanded to assess the extent of VDPV2 transmission in and outside of London.
The U.K. stated it is committed to global polio eradication, and achieving this is maintaining high vaccine coverage (95%) in the routine childhood immunization program.
Primary care colleagues and school-aged immunization providers should opportunistically check that patients are up to date with their polio-containing vaccines and provide catch-up vaccination to anyone who is un/under-vaccinated.
While the U.K. stopped using OPV in 2004, several countries, including Pakistan, Afghanistan, and Nigeria have continued to use OPV-containing type 2 virus for outbreak control.
Since 2000, the U.S. has offered the IPV vaccine.
To alert international travelers to this new polio risk, the U.S. CDC included the U.K. in the updated Alert - Level 2, Practice Enhanced Precautions notice on November 18, 2022.
Other polio outbreak news is posted at Vax-Before-Travel.com/Polio.