Polio Vaccine Warning As Virus Resurfaces in U.K. After Decades

A polio vaccine warning has been issued in the U.K after the virus was detected in the country for the first time in decades.

The virus was detected in sewage samples collected in east and north London, during routine surveillance, the UK Health Security Agency (UKHSA) said in a press release.

A national incident has now been declared in the country, as the agency warns citizens to ensure they are up to date with vaccinations.

The U.K. was declared free from polio in 2003 after routine vaccination was introduced in 1956. The last case time a case of "wild polio" was contracted was 1984.

"Investigation underway to protect public, who are urged to ensure polio vaccines are up to date, especially parents of young children who may have missed an immunization opportunity," the statement said.

There are so far no reported cases of the disease and the risk to the wider public is considered low—however the virus can spread through contaminated food, water and poor hand hygiene.

UKHSA said that investigations are currently underway, to determine whether the virus is being transmitted into the community.

So far, scientists have determined that this virus has evolved into a "vaccine derived," poliovirus type 2.

This strain of the virus can occasionally cause serious side effects, including paralysis. Vaccines, however, can reduce the risk.

Scientists believe it has likely spread through "closely-linked individuals" in the area, who are now shedding the virus in their feaces.

"Vaccine-derived poliovirus is rare and the risk to the public overall is extremely low," Dr. Vanessa Saliba, Consultant Epidemiologist at the UKHSA, said in a press release. "Vaccine-derived poliovirus has the potential to spread, particularly in communities where vaccine uptake is lower.

"On rare occasions it can cause paralysis in people who are not fully vaccinated so if you or your child are not up to date with your polio vaccinations it's important you contact your GP to catch up ... Most of the UK population will be protected from vaccination in childhood, but in some communities with low vaccine coverage, individuals may remain at risk."

What is polio?

Polio is a virus that has been around since ancient times, however it was not officially discovered until 1908.

The virus is rare, but can be extremely contagious. It usually spreads through personal contact. Once in the body, it lives in a person's intestines and throat.

It begins to circulate when a person does not wash their hands properly after using the toilet. It can then spread further when the person touches water, or food. It can be spread through respiratory droplets caused by a caught or sneeze, however this is less likely.

According to the World Health Organization, the U.K. has low risk for polio transmission because it has a high rate of vaccinated individuals.

Vaccination rates have however decreased over parts of London in the past few years, the UKHSA said.

What are the symptoms?

Most people will not even realise that the polio virus is in their system. They will usually fight off the virus while having no symptoms.

However according to the Centers for Disease Control and Prevention (CDC), 1 in 4 people will experience cold-like symptoms including a sore throat, fever, tiredness, headache and stomach pain.

In some rare cases, a proportion of infected people will develop serious symptoms. These can inlude paresthesia—which is a "pins and needles" feeling in the legs—meningitis and paralysis. Some people might also experience weakness in their arms, legs, or both.

Paralysis is the main cause for concern associated with polio, as it can be fatal.

Severe cases of polio can also cause post-polio syndrome. This is when those who seem to recover fully from the virus, experience symptoms later on in life.