More than 400 children around the world have recently contracted acute hepatitis, a higher number than usual. Experts struggle to understand what the underlying cause is. Here are six questions and answers to explain what we know so far.
1. What is hepatitis?
Hepatitis is an inflammation of the liver that can be caused by viral infections (including Hep-A, Hep-B and Hep-C viruses), alcohol consumption, toxins, medications and certain abnormalities. medical.
Symptoms are nausea, vomiting, abdominal pain, dark urine, jaundice, fever and fatigue.
Chronic hepatitis rarely occurs in children and the exact cause is often difficult to determine. Dr. also recalled. Theresa Tam, Canada’s Chief Public Health Officer, this week that, even before the pandemic, nearly half of cases of severe pediatric hepatitis had no known cause.
In Canada, we see cases of non -specific hepatitis every year, maybe two or three, on averagesaid Dr. Fernando Alvarez, director of the liver transplant program at university hospital San Justine.
2. How many cases have been reported?
According to a report released this week by the European Center for Disease Prevention and Control (New window)currently there are approximately 450 cases worldwide and 11 deaths (5 in Indonesia, 1 in Palestine and 5 in the United States).
In the UK, there are more than 160 children under the age of 16 affected. Eleven of them received a liver transplant. In the United States, where 109 cases were identified, 90% of children were hospitalized; fifteen of them require liver transplant.
Cases were also reported in Italy (36), Portugal (22), Argentina (8), Brazil (8), Costa Rica (2), Indonesia (15), Israel (12), Japan (7), Panama (1 ). ), Palestine (1), Serbia (1), Singapore (1) and South Korea (1).
In Canada, on May 13, there were 7 cases in Ontario, 2 in Alberta and 2 in Manitoba.
It remains to be determined whether this number represents an increase in cases of unknown origin compared to previous years.wrote in an email a spokesman for SickKids hospital in Toronto.
Cases are still relatively rare, but there are enough serious cases to monitor the situation closelysaid Dr. Christopher Labos, Montreal epidemiologist.
The first cases were seen in Alabama, USA in October 2021, but researchers initially believed it was a local problem. It was not until early April that the UK informed theWHO an abnormally high number of cases.
Dr. pointed out. It is still extremely difficult to know with certainty the true number of cases of acute hepatitis in the world. Now that the international community is alerted, the more we can discover the cases, the more we can make associations between them and thus better understand the cause.
3. What hypotheses are analyzed to determine the cause?
Drs. Labos and Alvarez that the researchers did not decide on anything.
So far, environmental factors do not seem to be involved. Viruses commonly associated with viral hepatitis (Hep-A, Hep-B and Hep-C) were not detected in these children.
Another element is clear, according to Drs. Excess: vaccination against COVID-19 is not in question because most cases are under five years of age and have not yet qualified for vaccination against COVID-19. More than 65% of children with severe hepatitis in the UK and more than 80% of children in Europe are not vaccinated.
Everything else is possible. It may be a combination of factors that have caused cases of hepatitissaid Dr. Alvarez, and added that one should not jump to early conclusions.
Dr. suggests. It is quite possible that some of the recently reported cases are relevant, while others are not. The cause may not be found for some of these cases.
So far, authorities and researchers are primarily looking at two possible causes: an adenovirus and SARS-CoV-2.
4. Could an adenovirus be the cause?
According to Dr. Caroline Quach, microbiologist-infectiologist and pediatrician at university hospital Sainte-Justine, the adenovirus theory seems the most convincing. This theory is also currently prevalent in the United Kingdom.
Adenoviruses are viruses that are spread through close personal contact. There are more than 50 types that can cause infections in humans (respiratory diseases, gastroenteritis, conjunctivitis, cystitis and, more often, neurological diseases).
According to the latest report fromWHO (New window)of 169 cases, 74 children tested positive for adenovirus, including 18 for adenovirus 41. In children, it usually causes chronic gastroenteritis that presents as diarrhea, vomiting and fever.
In the UK, 72% of children test positive for adenovirus. In Alabama, 7 out of 9 children are infected with the adenovirus.
But according toWHO, although adenovirus is currently thought to be an underlying cause, it does not fully explain the severity of the cases.. For example, no child in Israel with severe hepatitis has tested positive for adenovirus.
" This adenovirus has been detected in some cases, but not in all. This may be a realistic theory, but it doesn’t explain everything. "
Also, according to Dr. Alvarez, adenovirus type 41 is not commonly known to cause hepatitis in healthy children. In those without medication or not immunosuppressed, hepatitis caused by adenovirus is usually mild or almost nonexistent.
Dr. Quach, like other experts, wonders if the adenovirus possibly involved has a different genotype, leading to more severe lesions than commonly seen.
Researchers also wonder whether the fact that children were less exposed to adenoviruses during the pandemic may partly explain the increase in hepatitis. Sudden and more frequent exposure to adenoviruses when sanitary measures are removed may have resulted in a stronger immune response in some, resulting in acute hepatitis.
5. What about SARS-CoV-2?
Researchers are also investigating the potential role of SARS-CoV-2.
Another theory is COVID-19, which is not surprising given the recent number of cases, particularly in the UK and US, where many cases of hepatitis have been reported. But not all children with hepatitis test positive for COVID-19said Dr. Labs.
According to Dr. Alvarez, knows that COVID-19 infection may increase the incidence of hepatitis in some people, but, in general, this hepatitis is not as serious as those currently studied.
In Israel, 11 out of 12 children had COVID-19. However, of the eight cases recorded in Alabama, no one was diagnosed with COVID-19 when admitted to the hospital. However, it is not known whether these children have been infected in the past and it is not known how many other children with hepatitis in the United States have been infected with COVID-19.
In the UK, only 18% of children test positive for SARS-CoV-2 while in hospital. In Scotland, 8 out of 13 children test negative on the PCR test.
In Europe, (New window) Only 12% of 173 cases were diagnosed with COVID-19 by PCR test. On the other hand, of the 19 cases in which a serological test was performed (to detect a previous infection), 74% were positive for COVID-19. This is why some researchers believe that a serological test should be performed on all children with severe hepatitis to find out how many of them have been infected with SARS-CoV-2 in the past few months.
Moreover, researchers in India (New window) estimate that COVID-19 may have caused dozens of unexplained cases of acute hepatitis between April and July 2021.
Their unreviewed study shows that of 475 children with COVID-19, 47 had severe hepatitis. Of these 47 children; 37 were classified as having what the researchers called hepatitis associated with COVID-19 .
The only common factor we found was they were all infected with COVID-19 or they had all had a previous COVID-19 infection.told the CBC (New window) Dr. Sumit Rawat, leading author, microbiologist and associate professor at Bundelkhand Medical College, Madhya Pradesh, India.
He added that hepatitis cases dropped sharply as COVID-19 infection rates dropped, but increased when the number of cases was high. According to Dr. Rawat, this is another sign that COVID-19 may be involved.
Another hypothesis, presented by researchers in The Lancet (New window)is a co-infection of adenovirus and SARS-CoV-2 that possibly causes these hepatitis.
6. Should parents worry?
The three doctors said authorities should be alert, but not panic. The number of cases remains relatively low, they recall.
For most children, gastrointestinal upset is a common illness. But as always, it is necessary to consult if it lasts more than a few days and if there are signs of jaundice in the eyes.said Dr. Alvarez.
Dr. would like to remind. Quach to you that adenovirus is easily broken down using common cleaning products. We must continue to maintain our standard hygiene habits.
For his part, Dr. added. It is very wise to continue to protect children from COVID-19 by wearing the mask in crowded and enclosed areas. This is common sense, even if we discover that SARS-CoV-2 is not the cause of hepatitis.
Source: Radio-Canada
