What is causing the spike in severe hepatitis in kids? Not COVID vaccines

An apparent spike in cases of severe acute hepatitis in children is receiving a lot of media attention, perhaps more than would normally be the case, probably as a result of our current virus paranoia.

The WHO is reporting around 350 cases worldwide, and cases have been reported in some 20 different countries, although only 6 countries have reported more than 5 cases, including the USA, India, Indonesia and Canada, which is currently reporting 7. Six children have undergone liver transplants as a result of the infection, and 8 deaths have beem reported, 5 in the USA and 3 in India.

So, it's a nasty outbreak, even if it pales into insignificance against many other diseases. What's particularly alarming about it, though, is that researchers are not sure what is causing it. The usual hepatitis viruses A through E are apparently not the main cause, and it is not yet clear whether COVID-19 is implicated in some way. The most likely culprit is an adenovirus "F type 41", possibly in combination with COVID,  but even that does not seem to account for all the cases.

Of course, as you might expect, the internet has latched onto the idea that COVID vaccines are causing the hepatitis cases. Unfortunately for the anti-vaxx crew, though, most of the children who have contracted acute hepatitis have not had the COVID vaccine -  the affected children are mostly under the age of 5 and are not even eligible for the vaccine - which leaves rather a large hole in the argument. WHO states unequivocably, "hypotheses relating to side effects from COVID-19 vaccines are currently not supported as most affected children did not receive the COVID-19 vaccination". Oops.

Two widely-disseminated so-called studies that purport to link hepatitis to COVID vaccines have been broadly dismissed by researchers as either not relevant or not convincing. One is a single case report of a 52 year old man (not a study as such); the other was a general lab-based study of how COVID affects the liver and not related to any real-life cases (and was anyway released long before the current spike in children).

Of course, these kinds of nit-picky details won't hold back those who want to present ammunition against COVID vaccines on their favourite social media outlet. But they should.