• Health Adenovirus F41, the main 'suspect' of cases of childhood hepatitis

  • Infectious diseases Clues to the origin of rare childhood hepatitis: "Several hypotheses are considered: toxicological and adenovirus"

There are already 190 cases of childhood hepatitis of unknown origin.

Although each time the hypotheses are closer to the target of the problem.

Currently, the theory that is gaining strength is that behind liver infections there is an adenovirus, specifically in 43% of them and more specifically in the F41 subtype.

Why is this pathogen now causing more cases?

The World Health Organization (WHO) has put on the table that it may be due to a rebound in this microorganism after two years in which the predominant virus has been the coronavirus in its different variants.

The explanation offered by pediatricians is that "there is a lack of training of the immune system" to certain viruses, "which due to the certain situations of these two previous years caused by the pandemic have not suffered", explains Teresa Cenarro, a pediatrician in Zaragoza and spokesperson for the Spanish Association of Primary Care Paediatrics (Aepap).

In the United Kingdom they have clung 'strongly' to this theory.

Adenoviruses are microorganisms to which children should be exposed from infancy, "because they live with them, as with others," Cenarro explains.

In these two years, the prevalence of SARS-CoV-2 with its different faces (or variants) would have cornered the rest of the viruses, which, as the experts point out, "there have only been upticks when the transmission of the coronavirus was lower".

With the infections in the little ones, the hypothesis can be established that "now, since last winter, Covid is no longer the only virus in circulation and the rest are recovering their 'place'. Many little ones who should have faced these pathogens do it later and with a less trained defense system", explains Cenarro.

In addition, he adds that "the number of distancing, hygiene and prevention measures against covid, now more relaxed, would also have prevented it."

A few days ago, the researchers who are analyzing the cases detected in Scotland also pointed in the same direction in a paper published in

Eurosurveillance

.

The relative return to social normalcy after pandemic restrictions could explain this effect of adenovirus infection, the scientists suggested.

Thus, children would now be facing viruses with which, under normal conditions, they would have been in contact since their first months of life.

One possibility, he pointed out, is that children who have spent more than two years under the prevention measures established by the pandemic have had "less contact with adenoviruses" and, therefore, have not developed the expected immunity against them.

The pediatrician from Zaragoza points out that "in these months we have seen a 'potpourri' of common viruses prior to the pandemic, many of them adenoviruses."

But the problem is that "there is no monitoring of all circulating adenoviruses," explained yesterday from the European Center for Disease Prevention and Control (ECDC), its director Andrea Ammon.

In addition, she explained that there are a total of almost 200 cases and about 40% have occurred in European countries, although she noted that these figures "sometimes are not accurate because many cases are still being verified."

In turn, supporting this theory from the United Kingdom, Meera Chand, director of clinical and emerging infections at the Health Security Agency, has pointed out that, although no hypothesis is ruled out, "in the United Kingdom adenovirus infection has been identified in the 75% of affected patients".

In recent weeks, a significant increase in the circulation of adenoviruses has also been observed in the country.

The increase contrasts with the low transmission previously detected, during the peak months of the pandemic.

In this sense, although the possible implication of other toxic or environmental factors is still being investigated, it is especially studied whether these hepatitis are related to a greater susceptibility to exposure to adenovirus.

There is also the possibility, Chan added, that "new adenovirus variants" or other pathogens of interest are currently circulating.

On the other hand, the authorities are also investigating whether previous infection with SARS-CoV-2 or other viruses may be favoring a greater vulnerability of some children.

From the WHO, Philippa Easterbrook, senior scientist in the Global Hepatitis Program, explained yesterday at a press conference that "there have been unexplained cases during confinement."

This is happening now that an exhaustive study of infections is being carried out from the month of April backwards.

"We have found that in some countries there has been community transmission of adenoviruses. But we need more additional work to determine the rate of adenovirus in the population," Easterbrook stressed.

The problem is that this theory only adapts to a patient profile, not the global one.

Antonio Rivero-Juárez, a researcher at CiberINFEC and at the Infectious Diseases Unit of the Reina Sofía University Hospital and Maimónides Institute for Biomedical Research of Córdoba (Imibic), believes that "this is not enough", because there are "older minors up to the age of 16.

For this reason, all lines of investigation remain open.

In the conclusions presented at the Congress of the European Society for Clinical Microbiology and Infectious Diseases (ECCMID), a wide range is considered, ranging from a cofactor that makes adenovirus infections more serious;

a new variant of adenovirus;

a drug, toxin, or environmental exposure;

a new pathogen;

or even a new variant of SARS-CoV-2.

Regarding the latter, Rivero-Juárez explained to this newspaper that "a small percentage of children with Covid reinfections have been found."

But nevertheless, everything "is up in the air and we must have more data to be able to establish a direct link. Today it is still not possible," she concluded.

Conforms to The Trust Project criteria

Know more

  • AIDS and hepatitis

  • Infectious diseases

  • Pediatrics

  • Coronavirus

  • United Kingdom

  • Saragossa

  • covid 19