London primary-school pupils not fully vaccinated against polio are to be offered catch-up jabs after Easter.
The disease, common in the UK in the 1950s, was eliminated by 2003. But poliovirus traces were found in north and east London sewage in early 2022.
An emergency vaccination-booster campaign in London last summer reached more than 370,000 children.
And in early November, the latest tests found less of the virus – but officials say there is no room for complacency.
Dr Vanessa Saliba, from the UK Heath Security Agency, told BBC News: “We have early signs that there’s less spread of poliovirus in London – but we will need 12 months of no detections before the World Health Organization could declare that the UK is no longer an infected country.”
Polio causes paralysis in a very small number of cases where the virus attacks the nerves in the spine and base of the brain – but most are asymptomatic.
Last month, an eight-year-old in northern Israel was paralysed in an outbreak that saw three other children infected. And an unvaccinated man was paralysed by the virus in New York.
The vaccination schedule is normally:
- three doses before the age of one
- a booster at three
- another booster at 14
But only 88% of London children have had three doses by the age of one, compared with 92% in England as a whole.
“London is a very bustling, urban metropolis with lots of mobile populations, lots of diverse communities,” Dr Saliba said.
“We need to engage with these communities [so] that we get the messages across to them and that we make vaccine as accessible as possible.
“This is why the NHS is offering vaccinations through schools to children who have missed out.”