What causes acute hepatitis that affects British children?

In recent months, the number of cases of acute hepatitis in children under the age of 10 has risen sharply in the UK. Entre janvier et le 8 avril 2022, 74 cas ont été signalés à l’Agence britannique de sécurité sanitaire (UK Health Security Agency – UKHSA), 49 en Angleterre, 13 en Écosse et 12 autres répartis entre le Pays de Galles et northern Ireland.

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

(in 1Verse In May, the WHO received 228 reports of possible cases from 20 countries. More than 50 other cases are under investigation, including two in France](https://www.santepubliquefrance.fr/les-actualites/2022/hepatites-aigues-pediatriques-severes-d-origine-inconnue-point- de-status -au-29-April-2022), according to Public Health France, editor’s note)

Acute hepatitis is very rare in children, and the cause of this unusual increase in cases has not yet been established. The most likely theory is that these hepatitis are caused by a viral infection. Could it be related to infection with SARS-CoV-2, the coronavirus that causes Covid-19? Are there other explanations?

What is “hepatitis”?

First of all, let’s recall what hepatitis is and how it is related to a viral infection. The term “hepatitis” describes inflammation of the liver.

Inflammation is a nonspecific immune reaction that occurs after an infection or injury. It is a sign that the body is trying to fight a possible cause of the disease. 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 a high temperature.

Hepatitis can usually be treated with proper medical care. However, 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.

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

The causes of the disease can be varied, but hepatitis in children is usually associated with a viral infection. The most common viruses are the five hepatitis viruses: A, B, C, D, and E. Other viruses, such as adenoviruses, can also cause hepatitis, but are rarely involved.

What is unusual about pediatric hepatitis cases of concern is that none of the five hepatitis viruses have been detected in infected young patients. Which effectively rules out the most common cause of illness, and leaves public health authorities searching for an explanation…

Adenovirus and hepatitis

Adenoviruses are most commonly responsible for infection in humans, especially in children. Almost all of them had had an adenovirus at least once before the age of 10.

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

However, sometimes in immunocompromised patients (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 hepatitis.

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

The term hepatitis refers to inflammation of the liver.

Other possible causes

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

The observed cases can be, for example, caused by 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, affecting only about 10,000 people in the UK. Furthermore, autoimmune hepatitis is generally more pronounced in women, around the age of 45. Given these elements, it is unlikely that this disease was the cause of the outbreak observed in children.

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

In this regard, it is important to note that none of the children with hepatitis in the UK received the SARS-CoV-2 vaccine. So there is no reason to believe that vaccines meant to fight Covid-19 have any connection to this peak in hepatitis.

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

Finally, a completely different virus, which has not yet been discovered, can be the cause of these diseases.

And now?

The UK’s Health Safety Agency advises parents and caregivers to watch out for signs of hepatitis.

Although adenoviruses currently appear to be the most likely cause, more research will be needed to confirm this hypothesis, and to rule out other possibilities, such as infection with new viruses. We may discover that there is no common origin for these patients, and that their causes differ in different children.

Read more: We have a good chance of curing the common cold in the next 10 years – a scientist explains

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

In conclusion, if it is proven that the adenovirus is indeed responsible for this situation, how can we protect ourselves from it and thus reduce the risk of serious complications?

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

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