A wave of acute hepatitis is affecting British children, here is what we know – Edition du soir Ouest-France

By Conor MEEHAN, Lecturer in Microbiology, Nottingham Trent University (UK)

The SARS-CoV-2 responsible for the Covid has not yet been removed from the list of suspects. But the most likely culprit for the wave of severe hepatitis now affecting children in the UK is another virus, adenovirus.

In recent months, the number of cases of severe hepatitis in children under 10 has risen sharply in the UK. Between January and April 8, 2022, 74 cases were reported to the UK Health Security Agency (UKHSA), including 49 in England, 13 in Scotland and a further 12 split between Wales and Scotland. North Ireland. Other isolated cases have also been identified in the United States, Spain and Ireland. As of May 1, 2022, the World Health Organization (WHO) has received 228 reports of probable cases from twenty countries. More than 50 other cases were under investigation, including two in France, according to Public Health France.

Severe hepatitis is very rare in children, and the cause of this very unusual increase in cases has not yet been identified. The most likely theory is that these hepatitises result from a viral infection. Could they be linked to infection with SARS-CoV-2, the coronavirus that causes Covid-19? Are there other explanations?

What is “hepatitis”?

First of all, let’s remember what hepatitis is, and how it is linked to viral infections. The term “hepatitis” describes inflammation of the liver.

Inflammation is a nonspecific immune reaction that occurs after infection or injury. It is a sign that the body is trying to fight off a potential cause of illness. In children, symptoms usually include some (but not all) of the following: dark urine, gray stools, yellowing of the skin and eyes (called jaundice), and high temperature.

With proper medical care, hepatitis can usually be cured. Nevertheless, it happens that the condition of some patients requires a liver transplant. In mid-April, six British children had to undergo such a transplant, according to the World Health Organization.

The causes of the disease can be diverse, but in children hepatitis is usually associated with viral infections. The viruses most commonly implicated are the five hepatitis viruses: A, B, C, D, and E. Other viruses, such as adenoviruses, can also cause hepatitis, but are more rarely implicated.

What is unusual in the pediatric hepatitis cases of concern to us is that none of the five hepatitis viruses have been detected in the young affected patients. Which therefore effectively excludes the most common cause of the disease, and leaves public health authorities in search of an explanation…

Adenovirus and hepatitis

Adenoviruses are commonly responsible for infections in humans, especially in children. Almost all of them have been infected at least once with an adenovirus before the age of ten.

Usually, these viruses cause infections of the lungs and respiratory tract, which usually results in cold symptoms or, sometimes, pneumonia. In some cases, primarily in children five years of age and older, adenoviruses can also cause “pharyngoconjunctival fever” (pool fever, literally “pool fever”), which results in a sore throat, fever and inflammation of the eyes.

However, occasionally in immunocompromised patients (i.e. anyone whose immune system is not working properly, such as people who have had an organ transplant or are undergoing cancer treatment), adenoviruses rarely cause occasions hepatitis.

But it is extremely rare to observe such a number of cases, especially in children who do not seem to be immunocompromised. If an adenovirus is indeed the cause of these cases, it could mean that a new variant has emerged, capable of causing the disease more easily.

Hepatitis refers to inflammation of the liver. (Illustration: Explode/Shutterstock)

Other potential causes

Since adenovirus infection is a common infection in children, and can also result in hepatitis, it is tempting to consider this explanation as the most probable. But other scenarios must nevertheless be explored.

The cases observed could, for example, result from autoimmune hepatitis: in this disease, it is not a virus or another pathogen that attacks the liver, but the organism itself. However, this type of hepatitis is rare, affecting only around 10,000 people in the UK. What is more, autoimmune hepatitis generally manifests itself more in women, around the age of 45. Given these elements, it is very unlikely that this disease is the cause of the outbreak observed in children.

Another hypothesis suggests that Covid-19 could be the cause of these cases of hepatitis. Indeed, SARS-CoV-2 has been detected in some of the affected children (isolated cases of hepatitis have also been reported in Covid patients, but these are even rarer than autoimmune hepatitis and have mainly observed in adults with severe forms of Covid).

In this regard, it is important to note that none of the children diagnosed with hepatitis in the UK had received a SARS-CoV-2 vaccine. There is therefore no reason to think that the vaccines intended to fight against Covid-19 have any connection with this peak in hepatitis.

Another possibility: these hepatitises could result from an interaction between different viruses (for example, between an adenovirus and a coronavirus which would both infect the same child, at the same time).

Finally, a totally different virus, which has not yet been detected, could also be the cause of these diseases.

And now ?

The UK Health Safety Agency advises parents and caregivers to be alert for signs of hepatitis.

Although adenoviruses currently appear to be the most likely culprits, further research will be needed to confirm this hypothesis, and rule out other possibilities, such as infection by new viruses. Perhaps we will discover that there is no common origin to these hepatitises, and that their cause varies according to the children.

Either way, in the face of an unusual medical scenario such as this, and as the Covid-19 pandemic continues, we should always keep in mind that the coronavirus is a possible suspect. However, we should not systematically blame everything on him, because that would risk distorting our vision of things.

To conclude, if an adenovirus proves to be indeed responsible for this situation, how can we protect ourselves from it and thus minimize the risk of serious complications?

Adenoviruses are spread through the air and by touch. The main preventative measure is therefore, for adults and children alike, to wash their hands properly and to adopt good hygiene practices, for example by coughing into their elbow rather than into their hand.

The original version of this article was published in The Conversation.

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