[FILE IMAGE] A health worker shows a vial of polio vaccine during a government-led vaccination campaign in Manila on October 14, 2019 (Photo by Ted ALJIBE/AFP)
Around a million children in London will be offered a polio booster shot after the virus was detected in sewage samples across the capital, health officials said on Wednesday.
“Following the discovery of vaccine-derived poliovirus type 2 in sewage in north and east London,” a targeted booster would be offered to children aged one to nine, a health ministry statement said .
There have been no confirmed cases of the disease, but it has been found in an increasing number of sewage treatment plants in the capital. It was first detected in an East London treatment job earlier this year.
The levels detected suggest “that there is some level of virus transmission in these neighborhoods that may spread to adjacent areas,” the statement said.
The last case of polio, which can cause paralysis, in the UK was in 1984.
The wild version of the virus now exists only in Afghanistan and Pakistan, but a type of vaccine containing small amounts of weakened but live polio still causes occasional outbreaks elsewhere.
Oral polio vaccine (OPV) replicates in the gut and can be passed to others through faecal-contaminated water. So while it won’t harm the vaccinated child, it could infect their neighbors in places where hygiene and immunization levels are low.
Although weaker than wild poliovirus, this variant can cause severe illness and paralysis in people not vaccinated against the disease.
The discovery in the London sewage samples suggests that “there may be a localized spread of poliovirus,” polio eradication expert Kathlene O’Reilly said.
This would most likely be among people who are not up to date with their polio immunizations, he added.
Polio immunization coverage in London is almost 87 percent, according to the WHO, lower than the rest of the country.
“For the majority of the population, who are fully vaccinated, the risk is low,” said Vanessa Saliba, a consultant epidemiologist at the UK’s Health Safety Agency.
“But we know that areas of London where polio is transmitted have some of the lowest vaccination rates.
“This is why the virus is spreading in these communities and putting those residents who are not fully vaccinated at greater risk,” he added.