The Centers for Disease Control and Prevention is now investigating 109 cases of unexplained liver inflammation (hepatitis) in children as young as 25 in the past seven months. Of the 109 children affected, five died and 15 (14%) required liver transplants. All children were under 10 years old and 90% were hospitalized.
The CDC’s announcement on Friday marked a dramatic increase in cases reported in the United States, which was limited to nine confirmed cases in Alabama just three weeks ago. The cases also add to a growing global count, which reached more than 300 cases in more than two dozen countries.
But despite the rise in cases, the CDC and international health researchers are still baffled about the cause of the disease. Severe hepatitis is rare in young children, and unexplained cases of severe hepatitis are rarer.
So far, there have been no regular exposures, trips, medications, food or drinks related to the cases. The CDC and other health agencies have ruled out viruses that are known to cause hepatitis in children, such as hepatitis A to E viruses.
COVID-19 vaccination has also been ruled out as a possible cause, as most children have not been vaccinated; most are currently not eligible for vaccination due to their age. “Vaccination against COVID-19 is not the cause of these diseases, and we hope that this information will help clarify some of the speculation circulating online,” said Jay Butler, CDC’s Deputy Director of Infectious Diseases. press friday.
The CDC also ruled out SARS-CoV-2 as the cause, noting that the first known cases in Alabama were negative for the pandemic virus. These nine cases also had no history of SARS-CoV-2 infection. However, at a news conference on Friday, Butler noted that the agency is investigating antibody tests for affected children to determine if some have been previously infected with SARS-CoV-2, in case this could have a paper.
The UK Health Security Agency (UKHSA) and others have suggested that cases of hepatitis may be related to a previous SARS-CoV-2 infection with an additional factor that triggers hepatitis later.
However, the main hypothesis remains that an adenovirus contributes to cases in some way. Of the 109 cases reported by the CDC, Butler said more than half of them tested positive for an adenovirus. Of the five cases in Alabama that underwent subtype testing, all five tested positive for type 41 adenovirus.
At a technical briefing at the UKHSA also published on Friday, the agency reported that the number of cases in the UK had risen to 163. Of 126 cases tested for adenovirus, 91 (72%) tested positive. And of the 18 cases that were successfully subtyped, 18 were positive for type 41 adenovirus.
Adenoviruses are a large family of common viruses, most often associated with mild respiratory illness and pink eye in children. Adenovirus type 41, however, is a subtype that usually presents as a gastrointestinal disease. Adenoviruses are generally occasionally associated with cases of hepatitis, but these cases are almost exclusively in immunocompromised children. Most cases of unexplained hepatitis have occurred in previously healthy children.
At the UKHSA technical briefing on Friday, the agency listed its updated working assumptions.
“There is an increase in pediatric presentations of non-EA acute hepatitis due to:
- A normal adenovirus infection, due to one of [the possibilities below]:
a. Abnormal susceptibility or host response that allows adenovirus infection to progress more frequently to hepatitis (either direct or immunopathological), for example due to lack of exposure during the coronavirus pandemic (COVID-19) .
b. An exceptionally large wave of normal adenovirus infections, which causes a very rare or little-known complication to occur more often.
c. Abnormal susceptibility or host response to adenovirus due to previous SARS-CoV-2 infection (including restricted Omicron) or other infection.
d. Abnormal susceptibility or host response to adenovirus due to co-infection with SARS-CoV-2 or another infection.
e. Abnormal susceptibility or host response to adenovirus due to a toxin, drug, or environmental exposure.
- A new variant of adenovirus, with or without a cofactor contribution as indicated above.
- A post-infectious syndrome SARS-CoV-2 (including a restricted effect Omicron).
- A drug, a toxin or an environmental exposure.
- A new pathogen that acts alone or as a coinfection.
- A new variant of SARS-CoV-2 “.