There has been a sharp increase in severe hepatitis cases among children under ten in the UK over recent months. The UK Health Security Agency has been informed of 74 cases since January 2022, with 49 of these in England, 13 in Scotland and the remaining 12 spread between Wales and Northern Ireland.
Other isolated cases of severe acute hepatitis in children have been identified in the US, Spain and Ireland.
Severe hepatitis in children is very rare and we don’t yet know what’s causing this highly unusual rise in cases. The leading theory is that it’s some kind of viral infection, perhaps even SARS-CoV-2, the coronavirus that causes COVID-19.
But how likely is it that these hepatitis cases are linked to COVID? Or is there a more likely cause to be found elsewhere? First let’s break down what hepatitis is and how it’s linked to viral infections.
Hepatitis is the medical term for inflammation of the liver. Inflammation is a general immune response to an infection or injury – a sign the body is trying to fight off a potential disease. Symptoms in children usually include some (but not all) of the following: dark urine, grey-coloured faeces, yellowing of the skin and eyes (called jaundice) and a high temperature.
With the right medical attention the condition can usually be treated, but some patients may require a liver transplant. The World Health Organization has reported that six of the children affected in the UK have undergone a transplant so far.
The causes can be varied but in children, hepatitis is usually associated with viral infections. The most common of these are the five hepatitis viruses: hepatitis A, B, C, D and E. Other viruses such as adenoviruses can cause hepatitis, but this is rare.
What is unusual about these cases in children is that none of the five hepatitis viruses have been detected in any of the patients. This rules out the most common cause of these symptoms, leaving public health authorities searching for answers.
Adenoviruses and hepatitis Adenoviruses are a very common viral infection in humans, especially children. Nearly every child has at least one adenovirus infection before the age of ten.
Usually, these viruses cause infections of the lungs and airways, resulting in common cold symptoms and sometimes pneumonia. In some cases, mostly in children aged five and over, adenoviruses can cause what’s sometimes referred to as “pool fever”, resulting in a sore throat, fever and inflammation of the eyes.
In immunocompromised patients (anybody with an immune system that’s not functioning properly, such as those undergoing organ transplants or cancer treatments), adenoviruses can on rare occasions cause hepatitis.
But to see it on this scale is extremely rare, especially in children who don’t appear to be immunocompromised. If adenovirus is the cause of these cases, it could mean that a new variant of adenovirus has emerged that more easily causes hepatitis.
Other potential causes Adenovirus seems to be the most likely explanation, as it’s a common infection in children and can cause hepatitis. But there are some alternative scenarios that should be explored.
Autoimmune hepatitis, where the body itself attacks the liver (as opposed to a virus or other pathogen attacking it), could potentially cause such cases. But this is a rare condition, affecting roughly 10,000 people in the UK and usually found in women around the age of 45. With these things in mind, autoimmune hepatitis is very unlikely to be the cause of a cluster of cases in children.
There have been suggestions that COVID could be behind these cases of hepatitis, as SARS-CoV-2 has been detected in some of the children. Isolated cases of hepatitis have been reported in COVID patients, but this is even rarer than autoimmune hepatitis, and has mostly been observed in adults with severe COVID.
Importantly, none of the children diagnosed with hepatitis in the UK have received a COVID vaccination, so there’s no basis to believe COVID vaccines have anything to do with this spike.
Another possibility is that this is a new symptom resulting from interaction between viruses (perhaps adenovirus and coronavirus both infecting the same child, for example). Alternatively, it could be caused by a totally different virus that hasn’t been detected yet.
What now? The UK Health Security Agency is advising parents and carers to be alert to signs of hepatitis in children.
While adenovirus currently looks to be the most likely cause here, further investigation will be needed to confirm this, and rule out other possible explanations such as novel viruses. It may even turn out that the cause is not common among all cases.
As the COVID pandemic continues, we must routinely consider coronavirus as a possible cause for unusual healthcare scenarios. At the same time, we shouldn’t assume there’s always necessarily a link. Such thinking carries the risk of blinding us to what’s really going on.
If adenovirus is found to be the main cause, what can we do to protect against it, and in turn minimise any risk of serious complications? Adenoviruses spread through the air and via touch. The main preventative measure is proper handwashing – by kids and adults alike – along with good respiratory hygiene, such as coughing into your elbow.
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