A wave of pediatric hepatitis has alarmed health authorities in Europe and the United States. Dozens of children have been diagnosed in five countries, including acute cases of the disease, since early April. The cause is still a mystery: none of the five known hepatitis viruses were found in blood tests.
“Very Strange”, “Extremely Amazing” or “Unusual and Related”. About a month ago, these terms were used in interviews with virologists and pediatricians about the emergence of cases of liver inflammation in young children, which led to the need for liver transplants for certain patients.
The first outbreak occurred in Scotland in early April. Subsequently, other children were diagnosed elsewhere in the UK. A total of about 80 patients, aged between 22 months and 13 years, were enrolled, according to the UK Health and Safety Agency.
Since then, other cases of childhood hepatitis have been reported in Spain, Denmark and the Netherlands, according to the European Center for Disease Prevention and Control. At least nine sick children are being treated in the US state of Alabama.
So far, experts do not know what causes childhood hepatitis. Tests failed to detect the presence of the known hepatitis virus, A to E.
Very rare acute hepatitis in children
The number of infections appears to be low, but it was enough to alert the WHO (World Health Organization). The agency has issued a warning to other countries to be aware of similar cases, which could increase the number of patients “in the coming days”.
The seriousness of the cases has caught the attention of experts. “Hepatitis is a very rare condition in children and it is an acute case, which is even more rare,” said Will Irving, a virologist at the University of Nottingham.
Hepatitis is often caused by a child’s habit of moving away from the world, such as excessive alcohol consumption, sexually transmitted infections, or drug use. Also, the disease often has mild symptoms, such as fever, diarrhea, abdominal pain, and yellowing of the skin.
However, in the case of this wave diagnosis, “almost all the children’s livers were severely damaged,” said Will Irving.
Graham Cook, an infectious disease specialist at Imperial College London, said that in at least six cases, children had to have a liver transplant, a very rare condition.
There is a cause for this hepatitis that, for the time being, is being treated as “mysterious” because no known hepatitis virus has been found in patients’ tests.
Also, common environmental factors that may explain the disease, such as eating contaminated food or exposure to certain toxins, have not been identified.
The geographical distribution of patients on both sides of the Atlantic further reduces the likelihood of finding an explanation associated with the local factor.
Impossible link with Covid-19
Due to the epidemic, experts are studying the possibility of a relationship with the Kovid-19 virus. “This could be a still unknown effect of the last omikron variant,” said Alastair Sutcliffe, a pediatrics researcher at University College London.
However, experts are skeptical of this possibility. First, because many of the infected children did not have Covid-19 at the same time. Second, if it were a still-unknown symptom of CoVID-19, the rate of spread of SARS-CoV-2 would probably lead to much more hepatitis, “said Will Irving.
British health authorities have even investigated whether it could be a side effect of the anti-covid vaccine, but none of the children have been vaccinated. “This is probably the only good news in this story,” notes Alistair Sutcliffe.
An adenovirus or a new virus
In contrast, an adenovirus is on scientists’ radar as a potential suspect: AD-41. The virus is part of a larger family that is often responsible for mild symptoms such as colds or fatigue. “It is known to cause gastroenteritis in children, but it has never been associated with a risk of hepatitis,” Will Irving noted.
The presence of this adenovirus has been detected in a number of children who have had “mysterious” hepatitis in the UK, and “we know that there is now a significant increase in the number of adenovirus infections in the UK population,” admitted Graham Cook.
“It is quite frightening to think that control and subsequent relaxation of sanitary systems [que permitiram a propagação do adenovírus] Could discover a new cause of hepatitis, “notes Alistair Sutcliffe.
However, AD-41 was not found in the bodies of all the young men diagnosed. “This does not necessarily refute the thesis of a link between this adenovirus and hepatitis case – we may not have looked in the right place – but it does weaken the hypothesis,” Cook admits.
So are we facing a new virus? “This would be great because we are still in the midst of an epidemic associated with a new virus,” said Alastair Sutcliffe.
This last hypothesis will be the easiest to examine. “We have advanced techniques for detecting the presence of foreign DNA or RNA – which suggests the existence of a virus – in the case of tissue taken from the liver of infected children,” Will Irving summarizes.
However, if all these children need to be investigated for exposure to the same toxins or contaminated food, it will be more difficult for experts to give us an answer as to what causes hepatitis.