Britain is launching a polio vaccine booster campaign for nearly a million children in London aged 9 and under, after confirming that the virus is spreading in the capital for the first time since the 1980s.
The UK Health Security Agency (UKHSA) has identified 116 polioviruses from 19 sewage samples this year in London, after first sending an alert about finding the virus in June.
The levels of poliovirus found and genetic diversity indicated that transmission was taking place in a number of London boroughs, the agency said on Wednesday.
No cases have yet been identified but, in a bid to get ahead of a potential outbreak, GPs will now invite some 900,000 children aged one to nine for booster vaccines, alongside a wider catch-up campaign already announced.
Immunisation rates across London vary but are on average below the 95 per cent coverage rate the World Health Organization suggests is needed to keep polio under control.
The UKHSA first raised the alarm in June, after finding samples of the virus during routine wastewater surveillance.
Samples of the virus have subsequently been found in several London boroughs including Barnet, Brent, Camden, Enfield, Hackney, Haringey, Islington, and Waltham Forest, according to the UKHSA.
"No cases of polio have been reported and for the majority of the population, who are fully vaccinated, the risk is low," said Dr Vanessa Saliba, consultant epidemiologist at UKHSA. "But we know the areas in London where the poliovirus is being transmitted have some of the lowest vaccination rates".
"This is why the virus is spreading in these communities and puts those residents not fully vaccinated at greater risk".
Symptoms of Polio
Polio is caused by a virus that spreads easily from person to person mainly through the faecal-oral route. It can be spread by poor hand hygiene and less commonly, through coughing and sneezing.
Symptoms can include:
- High temperature of 38C or above
- Sore throat
- Abdominal pain
- Aching muscles
- Feeling and being sick