In Britain, as in the rest of Europe, polio has been officially eradicated for decades. Now, however, the British health authorities are making a worrying discovery: polio viruses are romping about in London’s sewage. But there is no reason to panic.

The poliovirus, which causes polio, has been detected in a worrying number of sewage samples in London. According to the British health authorities, a live vaccine is probably to blame for the increased values. Because the disease has been eradicated in the United Kingdom since 2003, the last case occurred in 1984. There is no risk for the population due to the worrying finds. However, parents should ensure their children are fully vaccinated against polio.

The UK Health Security Agency (UKHSA) believes the virus was imported into London by someone who was recently vaccinated abroad with a live form of poliovirus. This type of vaccine has not been used in the UK since 2004. To date, however, all children are routinely immunized against the disease with an inactivated vaccine. Vaccination rates are lower in London than elsewhere in the country. Across the country, 92 percent of children have received the three shots needed for full immunization, compared to 86 percent in London.

According to the British health authorities, it is not unusual for isolated cases of poliovirus to be found in sewage. This time, however, the pathogens had been detected for over four months and in many different water samples from north and east London. Therefore, the authorities suspect that the virus was spread between people.

“Most of the UK population is protected by childhood vaccination, but in some communities with low immunization coverage, individuals may remain at risk,” says Vanessa Saliba, consultant epidemiologist at the UKHSA. Despite this, the authorities have declared a national emergency and informed the World Health Organization (WHO) of the situation.

Different polio vaccines with different vaccine schemes are approved for the German market. According to STIKO, only IPV (inactivated polio vaccines) are recommended as polio vaccine for routine vaccination in Germany. The basic immunization begins according to the STIKO vaccination calendar at the age of two months. There should be a minimum interval of six months between the last and penultimate vaccine dose as part of the primary immunization. A booster dose of a vaccine containing IPV is recommended between the ages of 9 and 16 years.

The oral vaccination against polio with weakened live viruses, which used to be common practice, has not been recommended by the STIKO since 1998. Because a person vaccinated with an oral vaccine can shed traces of the virus from their intestines, as may have happened in the UK. In rare cases, this form of the virus can then be transmitted to others and mutate into so-called “vaccine-related” polio, the BBC explains. Although this is weaker than the original or “wild” form of the disease, it can still cause serious illnesses and even paralysis in unvaccinated people.

Polio, or poliomyelitis, is a highly contagious infectious disease that primarily affects children under the age of five, endpolio.org informs. The virus is transmitted through personal contact and is most commonly found in contaminated water. The pathogen affects the central nervous system, causing paralysis and sometimes death. The Standing Vaccination Commission (STIKO) therefore recommends basic immunization against polio with a 6-fold vaccine for all infants and young children.