TThe most recent case of polio in the UK occurred in 1984 and was officially declared eradicated in 2004. .. A week after the poliovirus was found in several sewage samples in London, government health officials called it a "national incident." No new cases of polio have been identified in the United Kingdom, but according to awarning from the UK Health and Security Agency,, "some spread among closely related individuals in northern and eastern London. It may have been. Eliminates type 2 poliovirus strains from feces. "(Originally there were 3 types of poliovirus, but types 1 and 3 were not vaccinated.)
The virus detected in London's wastewater was not previously the so-called "wild" polio virus. It circulates freely around the world, but is currently eradicated in all but two countries, Afghanistan and Pakistan. Rather, it is what is known as a "vaccine-derived" poliovirus. There are two types of polio vaccines: an injectable version that immunizes with a killed virus and an oral version that uses a live but weakened virus. The oral version is the best vaccine for mass immunization because it is easier and cheaper to administer. However, at times, a harmless and weakened virus can mutate into an infectious paralytic form that can pass through the body with feces and infect individuals. That's what experts are afraid of what can happen in London.
Authorities have no way of knowing who the original source of the virus is, but probably because the UK switched from an oral vaccine to an injectable vaccine in 2004 for accurate prevention of this type. It was a visitor from another country. Vaccine-derived circulation. Although 86.6% of UK children are protected because they are vaccinated by injection, more than 13% are still vulnerable to the newly discovered virus, and authoritiesthese children Encourage (and those who don't) to. To be vaccinated against polio).
"Vaccine-derived poliovirus can spread, especially in communities with low vaccine intake," said Dr. Vabessa Saliba, an epidemiologist at the UK Health and Safety Department, in a statement in. Stated.
The presence of the virus in London is undeniably a nasty development, but it does not mean a public health emergency at all. Circulating vaccine-derived polio rarely causes paralysis, but like wild poliovirus, only 1 in 200 infected people will be paralyzed. The rest develop only cold-like symptoms or no symptoms at all.
Meanwhile, public health authorities are trying to track the original source of contaminated sewage from where the contaminated sewage was first identified. The problem is that the plant treats waste from millions of people and is unlikely to find it, even in the neighborhood where the virus has occurred, rather than an individual. The World Health Organizationreports that sewer pipes upstream of the factory are being sampled to more accurately identify the area of the contaminated city.
So far, the virus does not appear to be widespread within the community. If an infection is found, health officials can enter a strain of the virus and determine if it is the same as that isolated in the sewage sample. In any case, London's horror is a reminder that the long-sought goal of global eradication of polio is very close. The sooner it is censored in the remaining two endemic countries, the less the child will have to get sick again. Write to
Jeffrey Kluger (jeffrey.kluger@time.com).
