Traces of a form of polio, derived from a vaccine strain, were found in sewage samples taken from a treatment plant in London, the World Health Organization and British officials said on Wednesday.
“It is important to note that the virus has only been isolated from environmental samples – no associated cases of paralysis have been identified,” the World Health Organization said in a statement. Said.
WHO considers it “important for all countries, particularly those with high volume travel and contact with polio-affected countries and regions, to strengthen surveillance to quickly detect any imports of the virus and facilitate a rapid response.”
According to the World Health Organization, “the polio virus in any form poses a threat to children worldwide, wherever it is found.”
Polio is a highly contagious disease that invades the nervous system and can cause permanent paralysis.
The wild polio virus is the best-known form of the polio virus.
There is another type of poliovirus that can spread within communities: circulating vaccine-derived polioviruses, or cVDPV. While cVDPVs are rare, they have become more common in recent years due to low vaccination rates in some communities.
Circulating polioviruses derived from the type 2 vaccine (cVDPV2) are the most common, according to the Global Polio Eradication Initiative, a public-private partnership run by national governments with six major partners, including WHO.
A total of 959 cases were confirmed worldwide in 2020.
“Genetically Linked”
The British health safety agency said on Wednesday that “isolated” traces were found in “several sewage samples” taken from a treatment plant in London between February and June. This resort covers a large area north and east of the British capital and covers a population of around 4 million.
“These results suggest that there is likely to be localized spread of the polio virus among people who are not up to date on polio vaccines,” explains polio expert Kathleen O’Reilly.
In recent years, an average of 1-3 poliovirus isolates per year have been detected in UK sewage samples. However, these isolates were unrelated.
Currently, the British health safety agency states that “the isolates (…) are genetically linked”, making it necessary to study transmission of this virus in northeast London.
According to UK officials, the most likely scenario is for a newly vaccinated person to enter the UK before February from a country where the oral polio vaccine (OPV) is used in vaccination campaigns.
While the UK stopped using OPV in 2004, many countries including Pakistan, Afghanistan and Nigeria continue to use it containing type 2 viruses to control outbreaks.
Nicholas Grassly, professor at Imperial College London, explains that OPV is made from an attenuated form of live poliovirus that “grows in the gut for a short time, giving us immunity and can be detected in stool.”
“This virus can be transmitted occasionally and very rarely … can cause an outbreak of vaccine-derived poliovirus,” he says, noting that OPV was replaced by an injectable inactivated vaccine in England in 2004.
source: Noticias
[author_name]
