Some 101,737 children had not received a booster jab by their fifth birthday in 2020/21, out of a total of 693,928. Around a third of all these unprotected five-year-olds (34,105) were in London.
Uptake for a second polio booster is even lower in several parts of the country, including multiple London boroughs.
In Hillingdon, just 35 per cent of 14-year-olds had their school booster jab in 2020/21 – the worst coverage rate in the country. This is followed by Brent, where just a third of teens have been boosted. Poor uptake levels are also reported in Nottingham, Leicester and Middlesbrough.
It comes as health officials declared a national incident following the detection of poliovirus in London wastewater. The virus, which can cause paralysis in rare cases, was identified in sewage samples taken from the capital between February and May 2022.
Scientists fear the virus is silently spreading among communities in northeast London and has been begun to evolve.
The polio vaccine is given when a child is 8, 12 and 16 weeks old. And two further jabs are administered at 3 years and 4 months old, and at 14 years old. However, government data shows that not all children have receive the full five-shot course.
The regional percentages of five-year-olds who had not received their booster in 2020/21 ranged from 8.4 per cent in northeast England to 27.4 per cent in London.
In southwest England, 10.3 per cent did not get their first booster (given at the age of three years and four months), and 10.4 per cent of those in eastern England did not.
Separate data from UK Health Security Agency shows that 123,132 children aged 14 had not received a teenager booster jab in 2020/21, while 502,247 had.
The regional breakdown of those who had not received a teenage booster ranged from 16.1 per cent in south-east England to 23.2 per cent in the South West.
More recent quarterly data, for October to December 2021, shows that nearly a third of children in London had not had a booster by the age of five, while the figure was more than one in 10 across the rest of England.
UKHSA said it was “likely” there has been spread of a vaccine-derived poliovirus type 2 (VDPV2) between closely linked people in northeast London, with infected individuals believed to be shedding the virus in their faeces. So far, no suspected cases have been reported or confirmed.
The rise of VDPV2s throughout the globe is threatening attempts to eradicate polio. They are a rare, mutated version of the virus – typically found in under-immunised communities with poor sanitation – which derive from the live oral polio vaccine (OPV).
People vaccinated with OPV, which has not been used in Britain since 2004, can briefly shed traces of the vaccine-like poliovirus in their faeces. Samples of this kind are detected up to three times a year in UK sewage, likely from peopled inoculated overseas, and are considered normal, the UKHSA said.
However, the viral samples found earlier this year at London Beckon Sewage Works, which covers 4 million people across the northeast of the capital, appear to be related and share mutations. This suggests the virus is spreading and evolving.
It’s likely the virus was introduced to the UK in early 2022 by a person vaccinated with the OPV in an overseas country, who then began shedding the virus. From there, it may have then transmitted within a single family, before later spreading among individuals who aren’t fully vaccinated.
With patchy coverage across parts of the country, scientists have urged not fully protected people to come forward and complete their vaccination courses.
“Multiplication of vaccine-derived polio viruses can only happen if there is poor immunity against polio in the community, and with polio vaccine coverage at only 86 per cent in London we have a potential pool of susceptibles,” said Beate Kampmann, a professor of paediatric infection and immunity at the London School of Hygiene and Tropical Medicine.
“Hence the mission now has to be that everyone looks at their immunisation books and gets their series completed, so we close the gap and don’t allow these strains to spread.”
Most people who get polio do not have symptoms but some suffer mild, flu-like issues such as a high temperature, extreme tiredness, headaches, vomiting, a stiff neck and muscle pain.
In one in 100 to one in 1,000 infections, the polio virus attacks the nerves in the spine and base of the brain and can cause paralysis.