Polio vaccine: what happened to the poliovirus booster shot rollout for London children?

After far-reaching information campaigns when polio was discovered in London wastewater last year, the NHS won't be drawn on why a preventative booster shot campaign for children was quietly "paused".

In June last year, public health officials declared a national incident after traces of poliovirus were discovered in sewage samples collected from the London Beckton Sewage Treatment Works. Then in August, it was revealed the virus had been detected in North and East London’s sewage, in the Barnet, Brent, Camden, Enfield, Hackney, Haringey, Islington, and Waltham Forest areas. Lower concentrations were also found in areas around the Beckton catchment.

The UK Health Security Agency (UKHSA) warned the levels and high genetic diversity of poliovirus found suggested there was some level of virus transmission in those boroughs. “This suggests that transmission has gone beyond a close network of a few individuals,” it said.

In response, London children aged between one and nine were offered a booster dose of the polio vaccine. The rollout - which was widely publicised and covered by local and national media - started in areas where the virus had been detected and vaccination rates were low, before being extended to the rest of London’s boroughs.

But not long after, the polio page on the NHS website was reviewed to say the extra polio vaccine dose offer in London had been “paused”. No reasons were given, but more information would be available in 2023, the page said.

North and East London councils - like the Hackney London Borough Council - updated their information pages on the vaccination offer in early January, to read: “The polio booster offer in London is currently paused. Information on the future of the programme will be available shortly”.

“If you already have a GP appointment booked for the polio booster, you should still attend. However, walk-in vaccination sites and pharmacies will no longer provide this service,” the page said.

Why did the polio booster programme end?

When queried as to why the programme had been paused, an NHS London spokesperson said the London polio booster programme for children who were up-to-date on their polio vaccinations ended on 23 December. "The NHS in London continues to offer polio vaccinations to those that aren’t up to date with their routine vaccination schedule."

"We urge all parents of eligible children who aren’t up to date with their routine polio vaccinations to book an appointment with their GP practice to catch up," they said.

But the NHS would not be drawn on giving an explicit reason why the booster programme had ended. A spokesperson said: "I don't think there's anything we can add to the statement, except to say that UKHSA are working with the [Medicines and Healthcare products Regulatory Agency] to monitor surveillance findings and the NHS in London will respond to any recommendations as needed. "

The UKHSA told NationalWorld sewage surveillance for the vaccine-derived poliovirus was ongoing in London, and has been expanded to key sites outside the city, including Birmingham, Bristol, Leeds, Liverpool, Manchester, and Sheffield. They would publish an update on their findings “in due course”.

No clinical cases of polio had been reported, as of mid-February, the agency said. NHS data showed that 368,399 inactivated polio virus doses were administered to 1-9 year olds in London between 10 August 2022 and 8 February 2023.

“While London has lower coverage compared to other regions, the majority of people have been vaccinated and the risk to the public overall is low,” UKHSA said. “We continue to encourage parents to contact their GP surgery if their child is not up to date with their polio vaccinations or any of the other routine childhood vaccinations.”

What is polio?

Polio is a serious illness and can cause life-long paralysis or other disabilities, and in some cases, death. There is no cure for polio, and immunisation is the only way to protect against it.

Although it is normal for "vaccine-like" polioviruses to be detected each year in UK sewage samples, a few in the the recent discovery have had sufficient mutations to be classified as vaccine-derived poliovirus, according to the UKHSA.

Vaccine-derived poliovirus is of greater concern as it behaves more like naturally occurring “wild” polio and may, on rare occasions, lead to cases in unvaccinated individuals.