Poliovirus Found in London Sewage

Vaccine-derived poliovirus type 2 (VDPV2), which rarely causes paralysis and other serious illness among those who are not fully vaccinated, was found in sewage samples collected from London, the UK. The detected VDPV2 is linked to individuals living in North and East London. The government of the UK urged its population, especially young children, to ensure their polio vaccines are up to date.

“People vaccinated with the oral polio vaccine can shed the vaccine virus in their stool for a few weeks after they are vaccinated. They can pass it on to others mainly through poor hand hygiene and contaminated food and water. In countries with low vaccine uptake, the virus can spread in communities and during the circulation, the virus gradually gains mutations and becomes closer to the natural polio virus,” said Vanessa Saliba, Consultant Epidemiologist, UK Health Security Agency.

Current investigations aim to discover if community transmission is taking place. While the UK is considered to be a polio-free country, health authorities are concerned about the national decrease of vaccine coverage among children.

“The majority of Londoners are fully protected against polio and will not need to take any further action, but the NHS will begin reaching out to parents of children under five in London who are not up to date with their polio vaccinations to invite them to get protected,” said Jane Clegg, Chief nurse, NHS London.

Countries around the world have been invited to increase surveillance to rapidly detect and respond to any new virus. Moreover, immunization coverage has to be promoted to protect children from the disease and its consequences. 

Mexico’s high vaccination coverage has made polio almost nonexistent in the country, as reported by the National Institute of Public Health (INSP). However, in the Americas, the vaccination coverage is not as high as would be desired. Early this year, the Pan American Health Organization (PAHO) urged countries in the region to strengthen their efforts to vaccinate children, as only 82 percent of them had the three required doses of the polio vaccine during 2020. Moreover, after the pandemic, vaccine coverage against some childhood diseases, such as polio, dropped in many countries in the region because the response to SARS-CoV-2 overwhelmed health systems, according to Carissa Etienne, Director, PAHO.

“The threat of the reintroduction of poliomyelitis is real. We cannot step back. The prevention of polio cases depends on having a vaccinated children population and a strong surveillance of the disease,” said Andrés de Francisco, Director of Family, Health Promotion and Life Course, PAHO.