Polio virus remains in London wastewater

The discovery was made in the northern and eastern parts of the city, thanks to routine monitoring of London sewage. according to UK Health Security Agency The extent of the infection should now be checked immediately.

Polio, which can cause severe paralysis, was common until the first half of the 20th century. Thanks to vaccinations, it has been almost completely eradicated. The most recent Swedish domestic case was registered in 1977.

But ironically The disease can also be caused by vaccination. Helen Norder, assistant professor at the University of Gothenburg and expert on both polio and viruses in wastewater explains:

– There are three types of wild polio: type 1, 2, and 3. Types two and three are extinct, while type 1 is still found in Afghanistan and northern Pakistan. But the vaccine used to fight polio in large parts of the world consists of a live vaccine that is genetically modified so that it does not cause disease, she said.

The advantage is that the vaccine can be easily distributed. All your gut antibodies need is a drop on the tongue. Then the vaccine comes out with the feces, which in the long run can lead to the spread of immunity, if others come into contact with the feces of the vaccinated person, if he does not wash his hands properly, for example.

But there is an obvious drawback, because when the vaccine passes through the intestine 10 to 15 times, it begins to change so that it returns to the wild type that causes the disease, says Helen Norder.

This virus is called A “vaccine-derived poliovirus” is a modified vaccine virus that has now been found in London. What worries the authorities is that the discovery was made in several successive measurements, indicating that one or more people are constantly releasing the virus and that this virus, which may subsequently evolve into a variant that causes polio, is spreading between humans. .

In Sweden, the oral vaccine has never been used. In the 1950s, Sweden went its own way when a Swedish bacteriological laboratory developed a vaccine based on the killed virus. However, such a vaccine has a drawback that it must be given by injection and in several doses.

Three years ago, the World Health Organization (WHO) recommended the use of the killed vaccine. It was this week 20 years ago, WHO declared Europe polio-free.