RIO – A mysterious type of acute hepatitis has drawn the attention of health authorities in different countries around the world in recent weeks. The disease, which affects children and is already being investigated even in Brazil, is not caused by any of the known hepatitis viruses (A, B, C, D and E) and could have among its causes a still uncertain relationship between the COVID-19 and one type of adenovirus.
The World Health Organization (SGD) has recorded 348 cases of the disease so far this week. Most of the children had gastrointestinal symptoms, jaundice, and in some cases acute liver failure and death. THE Ministry of Health has created a situation room to monitor the 41 suspicious events of acute childhood hepatitis of unknown origin recorded to date in the national territory. a teenager needed undergo a transplant in the hinterland of Pernambuco on Friday the 20th, and the matter is being investigated.
The first hypothesis was raised by the health authorities in UK. There the first cases were recorded and it was hepatitis caused by an adenovirus. Studies have shown that up to 70% of patients have tested positive for adenovirus 41F. It affects more children, young people and immunocompromised people. It causes a cold or intestinal problems.
“At first it was thought that the adenovirus would be the cause of acute hepatitis, but the fact is that it did not appear in all cases”, explained infectiologist Marcelo Simão, from the Federal University of Uberlândia, in Minas Gerais. “In many children who presented with severe conditions, it was not possible to isolate the virus; and in some cases where a transplant was performed, the virus was not found in the removed liver.
Experts also noted that many children had had Covid-19 before acute hepatitis. A study published in the Lancet last week then proposed a new hypothesis. According to the study, a combination of the two infections is the cause of acute liver disease.
The remaining Sars-CoV-2 particles in the intestinal tract of children are thought to serve as a trigger for the immune system to overreact to subsequent infection with the virus. adenovirus 41F. The coronavirus spike protein is considered a superantigen. It makes the immune system more sensitive. It would potentiate the effect of adenovirus 41F. As a rule, this virus does not cause more serious problems.
The reaction would be similar to that caused in the multisystem inflammatory syndrome. This condition has been identified in children with long-term covid. In these cases, there is an abnormal activation of the immune system due to the superantigen. It triggers an extremely inflammatory autoimmune reaction. Any subsequent exposure to an adenovirus could cause the body to react even stronger. This is what can happen in cases of acute hepatitis.
“The most accepted hypothesis today is that this hepatitis is caused by an exaggerated immune reaction caused by the combination of these two viruses that ends up attacking the liver,” said Simão, whose name is on the list of most influential scientists at Stanford University. in the world. “Why the liver? We do not know yet.”
The most accepted hypothesis today is that this hepatitis is caused by an exaggerated immune reaction caused by the combination of these two viruses.
Marcelo SimaoInfectologist at the Federal University of Uberlândia
Another question that has not yet been clarified, according to Simão, is why cases of acute hepatitis have only started to be noticed now, two years after the start of the pandemic. A possible explanation would be related to the Sars-CoV-2 variant currently in circulation.
For the president of the Society of Infectious Diseases of the Federal District, José David Urbaez Brito, the hypothesis of the combination of the two viruses is currently the most likely to explain the cases of acute hepatitis in children, although it does not is not yet closed.
“What’s different at this time in our lives is that we’re going through the ongoing modulation of a pandemic,” Brito said. “We are being bombarded minute by minute by an infectious agent circulating on a gigantic scale. Anything that pops up again might have something to do with it.
Data from the WHO and studies from Israel, the United States and India support the hypothesis. The Israeli work, coordinated by Yael Mozer Glassberg of the Schneider Children’s Medical Center, showed that eleven out of twelve children who had hepatitis had had Covid-19. None of them, however, tested positive for adenovirus.
WHO Europe pointed out in a report published this month that up to 70% of children under 16 who developed acute hepatitis had already been diagnosed with Covid-19. Additionally, the experts explained, other children may have had the disease mildly or even asymptomatically; that is, without an official diagnosis.
A case study carried out in the United States and published in the “Journal of Pediatric Gastroenterology and Nutrition” analyzed the case of a three-year-old girl. The girl developed liver failure days after recovering from mild covid.
“The patient’s liver biopsy and blood test results are consistent with a type of autoimmune hepatitis that may have been triggered by covid,” said pediatrician Anna Peters, a gastroenterologist at Cincinnati Children’s Hospital Medical Center. in the United States, responsible for the study, commenting on the work.
According to the expert, it is impossible to prove the existence of a direct link between covid and liver disease. But the virus may have triggered an abnormal immune response. She would be the generator of the liver attack.
A survey in India last year followed 475 children who had covid in the country. Among them, 47 had acute hepatitis. Recently, with the emergence of new cases in Europe and the United States, researchers turned their attention to this Indian study from 2021.
“The only common factor we found among these children was that they had all been infected with Covid,” said study lead author Sumit Rawat, an associate professor at the Bundelkhand School of Medicine in Madhya Pradesh, in India, in an interview with international agencies. “Proving that covid is in fact the cause of this hepatitis will still require many studies, but an important clue is that cases of hepatitis decreased when Sars-CoV-2 stopped circulating in the region and increased again when covid was high.”
The only commonality we found among these children was that they had all been infected with Covid.
Sumit Rawatprofessor at bundelkhand medical school
The link between hepatitis and the vaccine has been completely ruled out
The link between acute hepatitis cases and the covid vaccine, however, has been completely ruled out. There is no direct relationship between vaccination and hepatitis. In addition, the vast majority of children who presented with acute hepatitis were under the age of five. That is to say that they had not been vaccinated against covid.
Experts believe that new emerging viral pandemics – and their possible ramifications – are likely to become increasingly common due to human impact on the environment and climate.
“We live in a complicated world, with many new diseases, many new viruses; bacteria we don’t care about are now causing serious illnesses,” Simões said. “Despite advances in technology, the challenges are increasing.”
José David Urbaez Brito recalled that it is no coincidence that we live in the so-called Anthropocene period. It is the first time that a living being, in this case man, modifies its environment in such a profound and often irreversible way that it comes to name a geological era.
“Humans have changed geological and ecological chains, significantly increased global temperature, causing a profound impact on the dynamics of infectious agents, including viruses, which are very simple forms,” Brito said. “Stories have the power to rationalize what is happening, leaving us alienated; But the truth is that we are living in an apocalyptic moment of gigantic dimensions, and the current pandemic is a symptom of that. »