In recent months, the number of severe hepatitis cases in children under 10 has increased significantly in the UK. Between January and 8 April 2022, 74 cases were reported to the United Kingdom Health Security Agency (UKHSA), including 49 in England, 13 in Scotland and a further 12 split between Wales and Northern Ireland.
Other isolated cases have also been identified in the United States, Spain and Ireland.
(to 1uh In May, the World Health Organization received 228 probable case reports from 20 countries. More than 50 other cases were investigated, including two in France](https://www.santepubliquefrance.fr/les-actualites/2022/hepatites-aigues-pediatriques-severes-d-igine-inconnue-point-de -situation -au-29-April-2022), according to Public Health France, ed)
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 result from a viral infection. Could they be linked to infection with SARS-CoV-2, the coronavirus that causes Covid-19? Are there any 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 non-specific immune reaction that occurs as a result of an infection or injury. It is a sign that the body is trying to fight off a potential cause of 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 high fever.
With proper medical care, hepatitis can usually be cured. 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.
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The causes of the disease can be different, 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 involved.
What is unusual about the pediatric hepatitis cases that worry us is that none of the five hepatitis viruses have been detected in young affected patients. Which therefore effectively excludes the most common cause of the disease, and leaves the public health authorities looking for an explanation …
Adenovirus and hepatitis
Adenoviruses are commonly responsible for infections in humans, especially children. Almost everyone has been infected with an adenovirus at least once before the age of ten.
Usually, these viruses cause lung and respiratory infections, which usually cause cold symptoms or, sometimes, pneumonia. In some cases, mainly in children five years and older, adenoviruses can also cause “pharyngo-conjunctival fever” (“pool fever”), which causes sore throat, fever and inflammation of the eyes.
However, occasionally in immunocompromised patients (i.e. anyone whose immune system is malfunctioning, such as people who have undergone an organ transplant or are being treated for cancer), adenoviruses rarely cause occasional hepatitis.
But it is extremely rare to see such a number of cases, especially in children who do not appear to be immunocompromised. If an adenovirus is the cause of these cases, it could mean that a new variant has emerged, capable of causing the disease more easily.
Other potential causes
Since adenovirus infection is a common infection in children and can also cause hepatitis, it is tempting to consider this explanation as the most likely. But other scenarios still need to be explored.
The cases observed could, for example, derive from autoimmune hepatitis: in this disease it is not a virus or other pathogen that attacks the liver, but the organism itself. However, this type of hepatitis is rare and affects only around 10,000 people in the UK. In addition, autoimmune hepatitis generally occurs mostly in women, around the age of 45. Given these elements, it is very unlikely that this disease is the cause of the epidemic seen in children.
Another hypothesis suggests that Covid-19 could 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 also rarer than autoimmune hepatitis and are 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 vaccines designed to fight Covid-19 have a link with this hepatitis spike.
Another possibility: these hepatitis could result from an interaction between different viruses (for example, between an adenovirus and a coronavirus that 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’s Health Safety Agency advises parents and healthcare professionals to watch out for signs of hepatitis.
Although adenoviruses currently appear to be the most likely culprits, more research will be needed to confirm this hypothesis and rule out other possibilities, such as infection with new viruses. Perhaps we will discover that there is no common origin of these hepatitis and that their cause varies between children.
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Either way, faced with an unusual medical scenario like this, and as the Covid-19 pandemic continues, we should always keep in mind that coronavirus is a possible suspect. However, we should not systematically blame everything on him, as this could distort our view of things.
To conclude, if an adenovirus actually turns out to be responsible for this situation, how can we protect ourselves from it and thus minimize the risk of serious complications?
Adenoviruses spread in the air and by touch. The main preventive measure is therefore, for both adults and children, to wash their hands properly and adopt good hygiene practices, for example by coughing in the elbow rather than the hand.