LONDON –
Children aged 1-9 in London became eligible for booster doses of the polio vaccine on Wednesday after British health officials said they found evidence the virus had spread to multiple areas of the city but found no cases of paralytic human disease.
Britain’s Health Security Agency says it has found viruses derived from the oral polio vaccine in the sewage of eight London boroughs. The agency’s analysis of virus samples suggests that “transmission went beyond a narrow network of a few individuals.”
The agency said it has not found anyone infected with the virus and that the risk to the wider population is low. The decision to offer boosters to young children is a precautionary measure, it said.
“This will provide a high level of protection against paralysis and help reduce further spread,” the agency said.
The agency said it was also expanding wastewater monitoring to at least 25 more sites in London and across the country.
Most people in the UK are vaccinated against polio in childhood. According to the World Health Organization, only one in 200 polio infections results in paralysis; most people show no symptoms.
The health security agency said it was working closely with health authorities at the WHO and in the United States and Israel to investigate any links to polio viruses found in those two countries.
Kathleen O’Reilly, a polio expert at the London School of Hygiene and Tropical Medicine, said the polio virus circulating in London was “genetically related” to recent cases identified in the US and Israel.
“Further investigation is needed to fully understand how they are related, but it does show that this virus has the potential to cause disease,” O’Reilly said in a statement.
Polio is a disease that is often spread through water and mostly affects children under 5 years of age. It has mostly been wiped out from developed countries, but outbreaks remain in Pakistan, Afghanistan and parts of Africa.
Initial symptoms include high fever, fatigue, headache, vomiting and muscle stiffness. Among people paralyzed by the disease, death can occur in up to 10 percent of cases when their respiratory muscles become paralyzed.
In rare cases, the live virus contained in the oral polio vaccine used in global efforts to eradicate the disease can mutate into new forms potent enough to cause new outbreaks. The vaccination boost effort in London will use injected polio vaccines, which do not carry this risk.
“We know that areas in London where the polio virus is transmitted have some of the lowest rates of vaccination,” said Dr Vanessa Saliba, an epidemiologist at the Health Security Agency.
Add Comment