Public health officials are urging people to check their polio vaccine status is up-to-date after poliovirus was detected in sewage samples collected in London.
The UK Heath Security Agency (UKHSA) and the Medicines & Healthcare products Regulatory Agency (MHRA) found poliovirus in sewage samples collected from the London Beckton Sewage Treatment Works between February and May.
The virus is classified as a “vaccine-derived” poliovirus type 2 (VDPV2) which on rare occasions can cause serious illness, such as paralysis, in people who are not fully vaccinated.
It is likely there has been some spread between closely linked individuals in North-East London and that they are now shedding the type 2 poliovirus strain in their faeces, says UKHSA.
The virus has only been detected in sewage samples and no associated cases of paralysis have been reported but investigations will aim to establish if any community transmission is occurring.
Dr Vanessa Saliba, consultant epidemiologist at UKHSA said:
“Vaccine-derived poliovirus is rare and the risk to the public overall is extremely low.
“Vaccine-derived poliovirus has the potential to spread, particularly in communities where vaccine uptake is lower. On rare occasions it can cause paralysis in people who are not fully vaccinated so if you or your child are not up to date with your polio vaccinations it’s important you contact your GP to catch up or if unsure check your red book. Most of the UK population will be protected from vaccination in childhood, but in some communities with low vaccine coverage, individuals may remain at risk.
“We are urgently investigating to better understand the extent of this transmission and the NHS has been asked to swiftly report any suspected cases to the UKHSA, though no cases have been reported or confirmed so far.”
Jane Clegg, chief nurse for the NHS in London said:
“The majority of Londoners are fully protected against Polio and won’t need to take any further action, but the NHS will begin reaching out to parents of children aged under five in London who are not up-to-date with their Polio vaccinations to invite them to get protected.”
Polio can be spread by people not washing their hands after using the toilet and, less commonly, through coughing and sneezing.
The UK is considered to be polio-free with low-risk for polio transmission due to the high level of vaccine coverage across the population. However, vaccine coverage for childhood vaccines has decreased in parts of London over the past few years so the UKHSA is urging people to check they are up to date with their vaccines.