Over the past four months, the UK Health and Safety Service has detected the polio virus in samples collected from sewers serving a population of four million in north and east London.
British health officials say the polio virus has been detected in a worrying number of samples from London sewage.
The United Kingdom Health Insurance Agency (UKHSA) says it was most likely introduced to London by someone recently vaccinated abroad and notes that the risk is low, according to the BBC.
However, he emphasizes that parents need to make sure that their children are fully vaccinated.
“Most of the UK population is protected from childhood vaccination, but in some communities with low vaccination coverage, people are at risk,” said Dr Vanessa Saliba, an epidemiologist at UKHSA.
The UK National Vaccination Program includes a relevant childhood vaccine. It is given three times before the age of one year and then again at the age of three and 14 years.
However, many remain unvaccinated. Specifically in London only 86% are vaccinated with the three doses.
Over the past four months, the UKHSA has detected the polio virus in samples collected from sewers serving a population of four million in north and east London.
Scientists believe the virus came from someone who was immunized abroad with an oral vaccine that has not been used in the UK since 2004.
In rare cases, this form of the virus can then be transmitted to others and mutated into what is known as “vaccine-derived” polio.
Although milder than the original form of the disease, it can cause serious illnesses, including paralysis, in people who have not been vaccinated.
A small number of polio virus samples are detected each year in sewage, but this is the first time that a complex of genetically linked samples has been found repeatedly over a period of months.
Health officials say this suggests there has been some spread among close associates in London.
No actual cases of polio have been detected and there have been no reports of rare but severe symptoms in the UK.
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