Polio alert: why a national incident has been declared

A national incident has been declared as polio is spreading in the UK for the first time in nearly 40 years. 

The UK Health Security Agency (UKHSA) said that waste from sewage treatment works in Beckton, east London tested positive for the polio virus in February, with further positive samples detected since. 

Analysis of UK sewage normally shows up a few polioviruses each year, but the London samples detected since February “raised the alarm” because they are “related to one another and contained mutations that suggested the virus was evolving as it spreads from person to person”, reported The Guardian.

The outbreak is believed to have been triggered by someone returning to the UK after having been vaccinated with a live virus abroad, which then mutated into a type of polio “more like wild polio”, said The Telegraph. 

Britain was declared polio-free in 2003, and the “last wild case” of polio was detected in 1984, so this new outbreak is the “first new transmission event since the 1980s”, added the paper.

What is the risk to the public?

Officials believe that the spread is probably between “two closely linked individuals”, most likely “extended family members” who are now shedding the polio virus strain in their faeces, reported Sky News. 

Urgent investigations will now try to establish the extent of any community transmission and identify where it might be happening. 

However, health experts at the UKHSA have said that this type of vaccine-derived poliovirus is “rare” and the overall risk to the public is “extremely low”.

So far the virus has only been detected in sewage samples and no cases of the disease or related symptoms, such as paralysis, have been reported. Public health officials are urging people to make sure they and their families are up to date with their polio vaccinations to reduce the risk of harm.  

“Vaccine-derived poliovirus has the potential to spread, particularly in communities where vaccine uptake is lower,” Dr Vanessa Saliba, a consultant epidemiologist at the UKHSA, told the broadcaster.

“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.” 

Article source: https://www.theweek.co.uk/news/science-health/957157/polio-alert-why-a-national-incident-has-been-declared