The global count of unexplained hepatitis cases in children has reached about 450, including 11 reported deaths, according to an update from the European Center for Disease Prevention and Control.
The cases come from more than two dozen countries around the world, with some 14 countries reporting more than five cases. The countries with the highest number of cases so far are the United Kingdom and the United States.
In the UK, officials identified 163 cases in children under the age of 16, 11 of whom required liver transplants. Last week, the US Centers for Disease Control reported 109 cases under investigation in children under 10 years of age from 25 states. Of those cases, 14 percent required liver transplants and five children died.
Fourteen European Union countries reported around 106 cases combined, with Italy (35) and Spain (22) reporting the largest counts of the EU member countries. Outside the EU, officials reported cases in Argentina (8), Brazil (16), Canada (7), Costa Rica (2), Indonesia (15), Israel (12), Japan (7), Panama (1). , Palestine (1), Serbia (1), Singapore (1), and South Korea (1).
The 11 deaths were reported in Indonesia (5), Palestine (1), and the US (5).
The cause of severe hepatitis (inflammation of the liver) remains a mystery, despite the growing number. Some of the cases have been identified retrospectively, from October 1, 2021.
Health officials around the world have been on the lookout for childhood cases of acute hepatitis that cannot be explained by common causes, such as hepatitis A, B, C, D, and E viruses, which are known to damage the liver. Those with cases also have elevated levels of liver enzymes.
“Currently, the leading hypotheses remain those involving adenovirus,” Philippa Easterbrook, a senior scientist at the World Health Organization, said Tuesday in a news conference. “But,” she added, “I think [there’s] It also remains an important consideration about the role of COVID, either as a co-infection or as a past infection.”
Easterbrook noted that about 70 percent of cases that have been tested for an adenovirus have been positive, and subtype tests continue to commonly return adenovirus type 41.
Data coming soon
Adenoviruses are not known to cause hepatitis in healthy children, although the large family of viruses has previously been linked to liver damage in children with compromised immune systems. Adenoviruses often cause common respiratory infections in healthy children, while type 41 is linked to gastrointestinal illness.
Liver biopsy data have so far revealed no adenovirus in the livers of affected children, raising further questions. In addition, adenoviruses are quite common in children, and some of the hepatitis cases occurred while adenovirus transmission in the general population was high. This raises the possibility that the detection of adenoviruses is merely incidental and not the cause of the liver lesions.
At Tuesday’s press conference, Easterbrook pointed to the possibility, saying: “Hopefully, within the week, there will be UK data on [an] important case-control study comparing whether the detection rate of adeno in children with liver disease differs from that of other hospitalized children. That will really help determine if the adeno is just an incidental infection that has been caught or if there is a causal or likely link.”
Otherwise, officials have reported that the cases are sporadic and unlinked, with no known common exposures to drugs, food, drink, toxic substances, or travel. The US CDC has also ruled out bacterial infections, urinary tract infections, autoimmune hepatitis and a rare genetic condition called Wilson’s disease, based on data from cases in Alabama.
According to Easterbrook, tests have found that about 18 percent of cases are positive for SARS-CoV-2. However the The US CDC has ruled out SARS-CoV-2 as a possible direct cause of the cases, noting that the first nine cases identified in Alabama were all negative for the virus. At a news conference last week, CDC Deputy Director for Infectious Diseases Jay Butler said the agency is still keeping open the possibility that previous SARS-CoV-2 infections could play a role in the cases. Studies looking at past SARS-CoV-2 infections in affected children are now ongoing in the US and elsewhere.