What causes the acute hepatitis that affects British children?

In recent months, the number of cases of severe hepatitis in children under the age of 10 has risen sharply in the UK. Between January and 8 April 2022, 74 cases were reported to the UK Health Security Agency (UKHSA), including 49 in the UK, 13 in Scotland and a further 12 distributed between Wales and Scotland. Northern Ireland.

Other isolated cases have also been identified in the United States, Spain and Ireland.

(at 1 p.m.eh By May, the World Health Organization had received 228 reports of probable cases from 20 countries. More than 50 other cases were under investigation, including two in France](https://www.santepubliquefrance.fr/les-actualites/2022/hepatites-aigues-pediatriques-severes-d-origine-inconnue-point-de-situation -au-29-April-2022), according to Public Health France, ed.note)

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 hepatitis are due to a viral infection. Could they be associated with 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 associated with 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 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 attention, hepatitis can usually be cured. Nevertheless, it happens that some patients’ condition requires a liver transplant. In mid-April, six British children were to undergo such a transplant, according to the World Health Organization.

Read more: With all the focus on coronavirus, let’s not forget the other respiratory viruses

The causes of the disease can be different, but in children, hepatitis is usually associated with viral infections. The most commonly implicated viruses 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 that concern 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 the 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.

These viruses usually cause infections in the lungs and respiratory tract, usually resulting in cold symptoms or sometimes pneumonia. In some cases, mainly in children five years of age and older, adenoviruses can also cause “pharyngo-conjunctival fever” (“pool fever”), resulting in sore throat, fever and eye inflammation.

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

However, it is extremely rare to observe such a number of cases, especially in children who do not appear to be immunocompromised. If an adenovirus is actually the cause of these cases, it may mean that a new variant has emerged that can more easily cause the disease.

Illustration of hepatitis virus surrounding the liver
Hepatitis refers to inflammation of the liver.
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 likely one. But other scenarios still need to be explored.

The observed cases may, for example, be due to autoimmune hepatitis: in this disease, it is not a virus or another pathogen that attacks the liver, but the body itself. However, this type of hepatitis is rare and affects only about 10,000 people in the UK. In addition, autoimmune hepatitis generally shows up 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 may be the cause of these cases of hepatitis. In fact, 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 are primarily 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. Therefore, there is no reason to believe that the vaccines intended to combat Covid-19 have any association with this peak in hepatitis.

Another possibility: these hepatitis may be due to an interaction between different viruses (for example, between an adenovirus and a coronavirus, both of which would infect the same child at the same time).

Finally, a completely different virus that has not yet been detected may also be the cause of these diseases.

And now ?

The UK Health Safety Agency advises parents and relatives to be aware of 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 with new viruses. Perhaps we will find that there is no common origin for these hepatitis and that their cause varies according to the children.

Read more: We have a good chance of curing the cold in the next ten years – explains a scientist

Either way, in light of an unusual medical scenario like this, and while the Covid-19 pandemic continues, we should always keep in mind that coronavirus is a possible suspect. However, we should not systematically blame him as it may distort our view of things.

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

Adenoviruses spread through the air and by touch. The primary preventive measure, therefore, is for both adults and children to wash their hands properly and adopt good hygiene practices, for example, by coughing into the elbow instead of the hand.

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