Polio found in UK for first time since 1984, but risk of mass infection ‘low’

UK health officials have urged people to make sure they are vaccinated against polio, after several sewage samples in London tested positive for the poliovirus towards the end of June.

The UK Health Security Agency (UKHSA) said a poliovirus strain was detected during routine surveillance of waste water in February. A mutated version of the same strain was picked up again in the following months, suggesting the virus has spread between individuals, allowing it to evolve.

Nature.com reported the virus is called vaccine-derived poliovirus. It is a strain of (weakened) poliovirus that would have originally been found in oral polio vaccines, but has changed over time to behave more like a wild type, or naturally occurring, poliovirus. 

Vaccine-derived poliovirus can spread through faeces or respiratory secretions. On rare occasions, it can infect the nervous system, causing paralysis and breathing problems in unvaccinated people.

No people with symptoms of polio — including paralysis — have been reported so far, but health authorities are asking doctors to look out for, and report, any symptoms of the disease.

The last case of wild polio contracted in the United Kingdom was in 1984, and the country was declared polio-free in 2003.

Scientists say that, at the moment, there’s no reason to panic and that the form of virus that was detected in waste water poses a low risk to health: vaccination easily prevents the disease it causes, they said.