by Molly Walker, Deputy Managing Editor, MedPage Today May 12, 2022

As the CDC attempts to decipher the origin of the unknown acute hepatitis in kids, the agency released more detailed recommendations for adenovirus testing in these children on Wednesday.

Clinicians should continue to test for adenovirus among any child with "acute hepatitis of unknown etiology," and collect blood, respiratory, rectal, and potentially liver tissue specimens.

The CDC recommended the following parameters when testing for adenovirus:

The agency also added that when testing liver tissue or blood samples, nucleic acid amplification testing such as PCR is preferred, though it is "currently not available for FFPE liver biopsy or native liver explant."

CDC said that the 109 previously reported hepatitis cases, where 90% of children were hospitalized and 14% required liver transplant, are still under investigation, as well as the five suspected child deaths. The agency added that while adenovirus type 41 was detected in the five specimens available in the first cluster of nine cases, "investigators continue to examine the role of other possible causes and identify contributing factors."

The agency recommended that clinicians continue to report cases of hepatitis of unknown etiology to their local or state public health departments, and utilize their state public health laboratory for any diagnostic testing needs beyond their "local capacity."

Worldwide, 348 probable cases of the unknown acute severe hepatitis in kids have been reported in 21 countries, with 7.4% requiring a liver transplant, according to a Tuesday update from the World Health Organization (WHO). Most of these countries have reported 5 cases or fewer.

While adenovirus has been detected in blood samples for many of the cases, it has not been detected in liver tissue samples analyzed to date and "could be a coincidental rather than a causal factor," the WHO cautioned.

Molly Walker is deputy managing editor and covers infectious diseases for MedPage Today. She is a 2020 J2 Achievement Award winner for her COVID-19 coverage. Follow

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