Multiple countries are reporting outbreaks of acute hepatitis, an inflammation of the liver, in children. The cause has not yet been established although experts are hypothesising it may somehow be linked to COVID-19.
Since October 2021 over 600 cases have been reported worldwide. At the time of writing, the highest number of cases, 197, is in the UK and 10 children have required liver transplants but there have been no deaths. The US has the second highest number of cases, 180, and 15 children have required liver transplants.
Worldwide, 26 children have required liver transplants and 11 children have died. The youngest child affected was a one month old baby and the oldest was 16. The majority have been age 10 and under. No links between the individual cases or to international travel have been established. (1)
What do we know so far?
We know that the usual liver virus culprits (Hepatitis A, B, C, D and E) are not causing the disease. It may be a new virus or an existing virus but, with the pandemic, attention has naturally fallen on the COVID-19 virus. However, only some of the affected children have a proven history of COVID-19 infection.
There are already known links between COVID-19 and liver problems. Researchers in Italy first documented a case of hepatitis linked to COVID-19 in a ten year old boy in May 2021. (2)
Brazilian researchers also reported a case in a child in September 2021. (3)
Researchers in India have released a preprint of their study which found that 37 out of 475 children who tested positive for COVID-19 went on to develop hepatitis. (4)
Researchers at Case Western Reserve University School of Medicine in Ohio, USA have also found that children with COVID-19 have an increased risk of liver problems. (5)
What is not yet clear is if the COVID-19 virus is directly causing the hepatitis or creating the right circumstances for another virus to cause hepatitis eg by weakening the immune system.
Many of the children with hepatitis had proven infection with another virus known as adenovirus subtype 41. This is a virus well known to scientists that normally causes stomach bugs but is not usually associated with hepatitis. (6)
In the UK, of the 197 hepatitis cases 170 were tested for adenovirus subtype 41 and it was detected in 116 of the children. (7)
There is also a theory that prolonged lockdowns and school closures have led to young children’s immune systems not being exposed to the usual childhood viruses leaving them more susceptible to infections now. (8)
Although some have raised the possibility that this childhood hepatitis is linked to COVID-19 vaccination, the vast majority of children worldwide have not been given the vaccine and, in the cases of those children diagnosed in the UK, none had received the vaccine. (9)
In Conclusion
It is not yet known what is causing these cases of hepatitis in young children. The most likely scenario is that a series of events, rather than one specific cause, is the trigger.
Infection with COVID-19 may somehow be affecting the immune systems of children so that when they encounter other viruses, possibly the adenovirus subtype 41, their livers over-react and become inflamed and damaged. Alternatively, the lack of social contact during school closures and lockdowns may have resulted in children’s immune systems being shielded from the usual childhood viruses leaving them less well equipped to fight infections as life returns to normal.
A link to the COVID-19 vaccination can be ruled out given the fact that the vast majority of cases had not received any vaccine. Indeed, if the COVID-19 virus is proven to play a role in these childhood hepatitis cases, there could be a strong argument for rolling out the vaccine to all children.
(2)
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