- Jim Reed and Philippa Roxby
- Health Correspondents
Children in the UK are regularly vaccinated against polio, but uptake is lower than usual in London.
British health officials confirmed that the virus that causes polio was found in an alarming number of samples taken from sewage in London.
Polio was common in the UK in the 1950s but had been eradicated by 2003.
Britain’s Health Security Agency says the virus was likely brought to London by someone who was recently vaccinated abroad with a live version of the virus.
The agency says the risk is low, but parents should make sure their children are fully immunized against the disease.
Dr Vanessa Saliba, a consultant epidemiologist at the UK Health Security Agency, said: ‘Most of the UK population will be protected from a childhood vaccination, but in some communities where vaccine coverage is low, individuals may still be at risk. “.
In the UK the polio vaccine containing an inactive virus is used as part of a regular childhood vaccination programme. It is given three times before one year of age, then again at three years of age and finally at 13 years of age.
About 86 per cent of people get the vaccine in the first three doses in London, which is below target levels, where in the rest of the UK the proportion is more than 90 per cent.
The incident was reported nationally by British health authorities and reported to the World Health Organization.
Virus detected in sewage
Over the past four months, Britain’s Health Security Agency has found polio virus in samples collected from the Becton sewage system, which serves four million people in north and east London.
Scientists believe the source of the virus is a person vaccinated abroad with an oral polio vaccine containing a live version of the virus, which has not been used in the UK since 2004.
Then traces of the virus that were in the person’s intestines fell and made their way into the sewage, where they were discovered in the sample.
In rare cases, this form of the virus can pass to other people and mutate into what is known as “vaccine-derived” polio.
Although it is weaker than the original or “non-domesticated” form of the disease, it can nonetheless cause serious symptoms, including paralysis, in people who have not received the vaccine.
Each year a small number of samples of poliovirus are detected in wastewater monitoring, but this is the first time that a pool of genetically related samples has been found repeatedly in months.
Health officials say this suggests there have been some outbreaks of the virus among closely related individuals in London.
No real cases of polio have been discovered and there have been no reports of rare but serious symptoms in the UK.
Jane Clegg, the NHS chief nurse in London, said the agency would reach out to parents of children in London under five who have not updated their childhood dosages.
She also said, “Parents can also check their children’s vaccination status in the Red Vaccination Book, and people should contact a GP clinic to book a vaccination if they or their children are not fully immunized.”
Polio is a rare disease that spreads when a person does not wash their hands properly after using the toilet and then touches food or water that others have consumed, or, more rarely, through coughing and sneezing.
Most infected people will not show symptoms of the disease and will fight off the virus without even realizing that they were infected. A small number of people will have flu-like symptoms for up to three weeks.
In a very small number of cases, believed to be between 1 percent and 1 in a thousand, the polio virus attacks the nerves in the spine and at the base of the brain.
This may cause paralysis, which is usually in the legs. If the muscles responsible for breathing are damaged, it can be life threatening.