London, May 1 (IANS): Social media platforms have falsely linked the Covid vaccine with the recent spike in unexplained hepatitis in children across several countries, including the UK, the US and many others.

According to the UK Health Security Agency (UKHSA), the affected children were mostly under the age of five and therefore not eligible for the jab.

But social media posts on Twitter, Reddit, Facebook and Telegram reported false claims that these hepatitis cases were caused by the Covid vaccine, BBC reported.

The World Health Organisation had, till April 21, recorded at least 169 cases of acute hepatitis of unknown origin in about 12 countries.

Data from the European Centre for Disease Prevention and Control (ECDC) showed nearly 200 cases of hepatitis in children around the world.

So far, at least one child has died from the mystery strain of severe hepatitis, while 17 became so sick they needed liver transplants, the WHO said.

However, none of the five specific viruses (labelled A - E) which usually cause hepatitis was found, but the majority of youngsters tested did show up positive for a particular adenovirus -- a common family of infections responsible for illnesses from colds to eye infections.

While adenovirus can cause hepatitis, this is the first time the adenovirus-41 strain has been linked to several severe cases.

A post on Reddit highlighted the fact that an adenovirus is used in the AstraZeneca and Johnson & Johnson Covid vaccines.

However, the adenoviruses used in these vaccines are harmless transporters which have been modified so they cannot replicate or cause infection.

Not only are they completely different adenoviruses to the ones found in the affected children, but these vaccines are largely being restricted to use in people aged 40 and over in the UK, the report said.

Further, the average age of the children developing hepatitis is three -- an age group not eligible for any of the Covid vaccines in the UK, where most of the cases have been recorded.

An article claiming the Pfizer vaccine was to blame, was shared on Facebook in English, Spanish, Italian, Chinese and Norwegian. It quoted a much-misinterpreted study which has also been used to make misleading claims about the vaccines and fertility, the report said.

The health authorities are, however, analysing the role of Covid infection in these cases.

Small studies have found unusual cases of hepatitis in a handful of young children who had previously tested positive for Covid in Israel, Brazil, India and the US.

But experts think that at the moment Covid is not driving these cases.

"If you look at the number of patients, only 16 per cent tested positive for Covid, and this [hepatitis] is not the feature of Covid," Prof Anil Dhawan, a liver specialist at King's College Hospital London, was quoted as saying.

Hepatitis is a very rare known reaction to adenoviruses, he added.