More than 150 cases in ten countries, mainly in Europe: acute hepatitis affecting children raise questions and even fears of a new epidemic, but the origin of these severe inflammations of the liver remains unknown.
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It all started in the United Kingdom, which has the highest number of cases (114 now). Since then, cases have also been reported in Spain (13), Denmark (6), Ireland (less than 5), the Netherlands (4), Italy (4), France (2), Norway ( 2), in Romania (1), in Belgium (1), according to data from the World Health Organization (WHO).
Outside Europe, Israel (12 cases) and the United States (at least 9 cases) extend the list.
Affected children ranged in age from one month to 16 years old, but most were under 10 years old, and many under 5 years old. None had comorbidities.
There have been 17 kidney transplants, and one death.
“Investigations are continuing in all countries reporting cases. Currently, the exact cause of hepatitis remains unknown,” according to the European Center for Disease Prevention and Control (ECDC).
For now, an infectious cause seems to be considered the most likely, but no common link with contaminated food or a toxicant has been identified.
“You always have to take things seriously” and “watch closely”, but “don’t fall into psychosis either” because “we don’t even know where it comes from” until then, said Yazdan Yazdanpanah, chief of the infectious diseases department of the Bichat hospital in Paris and member of the French Scientific Council, in a recent interview with Express.
Hepatitis is an inflammation of the liver, in reaction to viruses, toxins (drugs, poisons, etc.), autoimmune or genetic diseases. Often of benign evolution, its main symptoms – fevers, diarrhoea, stomach pains, jaundice – quickly resolve or remain weak. More rarely, they can lead to kidney failure.
Acute hepatitis has been detected in sick children.
“The growing rise in the number of children with sudden onset hepatitis is unusual and worrying,” Zania Stamataki, of the University of Birmingham.
The fact that certain types of hepatitis affect small children, between 1 and 5 years old, surprises specialists even more, as does the need, in some cases, for a transplant.
And the usual viruses causing acute viral hepatitis (from A to E) were not detected in any of the cases, underlined the ECDC and the WHO.
Among the tracks under study, “adenoviruses” were detected in at least 74 children, including 18 of so-called “type 41” adenoviruses. Several countries, including Ireland and the Netherlands, have reported increased circulation of these adenoviruses.
Fairly banal and well-known viruses, adenoviruses generally cause respiratory symptoms (bronchitis, pharyngitis, etc.), ocular symptoms (conjunctivitis), digestive disorders (gastroenteritis).
Transmission occurs by the faecal-oral or respiratory route, with epidemic peaks often in winter and spring, and more often in communities (nurseries, schools, etc.). The majority of humans are infected before they are 5 years old.
But their role in the development of mysterious hepatitis is unclear.
If children infected with an adenovirus have suffered from hepatitis in the past, they were immunocompromised children. And adenovirus 41 is not known to cause hepatitis in healthy children, observes the WHO.
A new strain of adenovirus might therefore be involved, according to some British scientists.
Or other infections and environmental causes might exacerbate adenoviral inflammation.
The possibility of a link with COVID-19, which is still circulating, is also included in the hypotheses.
COVID-19 was detected in 20 of the children tested. And 19 other children showed co-infection with COVID and an adenovirus.
But “if these hepatitises stemmed from COVID, it would be surprising not to see them distributed more widely given the high circulation of Sars-Cov2”, observed Graham Cooke, specialist in infectious diseases at Imperial College London, with Science Media Center.
After more than two years of pandemic and barrier gestures, the question of an immune “debt” which would make certain children more fragile is raised by certain scientists, without certainty.
Finally, a possible role of anti-COVID vaccines has been ruled out: a large majority of children were not vaccinated, according to the WHO.
