CDC Does Not Find Increase in Pediatric Hepatitis Cases

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Acute hepatitis of unknown etiology is not reportable in the US, making it difficult to understand whether recent levels are now reaching historic levels.

A new US Centers for Disease Control and Prevention (CDC) report does not show an increase in pediatric acute hepatitis cases during the COVID-19 pandemic in comparison with pre-pandemic levels.

A team led by Anita K. Kambhampati, MPH, Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, CDC, assessed trends in hepatitis-associated emergency department visits and hospitalizations, liver transplantations, and adenovirus stool testing results in pediatric patients in the US.

Identifying the Problem

The CDC first identified a cluster of previously healthy pediatric patients with hepatitis of unknown etiology at a single US hospital in November 2021.

In April 2022, the CDC requested additional data on pediatric hepatitis cases of unknown etiology, which resulted in test results positive for adenovirus, which is not known to cause hepatitis in immunocompetent pediatric patients.

While adenovirus hepatitis is not uncommon in immunocompromised patients, adenovirus is not a recognized cause of hepatitis in healthy pediatric patients.

One issue is neither acute hepatitis of unknown etiology or adenovirus type 41 is reportable in the US, which makes it difficult to understand whether these levels are now reaching historic levels.

No Increase

However, there were 4 data sources that did not identify recent increases in hepatitis-associated emergency department visits or hospitalizations, liver transplants, or adenovirus types 40/41 percent positivity among pediatric patients compared with pre–COVID-19 pandemic levels.

“These data do not suggest an increase in pediatric hepatitis or adenovirus types 40/41 above baseline levels,” the authors wrote. “Pediatric hepatitis is rare, and the relatively low weekly and monthly counts of associated outcomes limit the ability to interpret small changes in incidence.”

In the study, the investigators compared data from October 2021- March 2022 with a pre-COVID-19 pandemic baseline using data from the National Syndromic Surveillance Program (NSSP), the Premier Healthcare Database Special Release (PHD-SR), the Organ Procurement, and Transplant Network (OPTN), and Labcorp.

The team compared weekly numbers of emergency department visits using a modified Farrington Method and compared monthly hospitalizations and liver transplants using the Wilcoxon rank sum test.

The results did not show an increase in weekly emergency department visits with hepatitis-associated discharge codes during the pandemic among patients aged 0-4 years or 5-11 years compared to the pre-COVIID-19 figures.

Between January 2019 and March 2022 there was a median of 22 and 10 hepatitis-associated hospitalizations in those age groups, respectively, recorded each month.

There was also no significant changes observed in hepatitis-associated hospitalizations during the pandemic study period, compared to the same months prior to COVID-19 among pediatric patients aged 0–4 years (22 and 19.5, respectively, P = 0.26) or 5–11 years (12 and 10.5, respectively, P = 0.42).

There was a median of 4 liver transplants in individuals younger than 18 years during each month between January 2017 and March 2022.

However, there was not a significant increase in the number of monthly liver transplants between October 2021 and March 2022 compared to the same months between 2017-2019 (P = 0.19).

Finally, the monthly number of adenovirus tests ranged from 184-1759 between October 2017 and March 2022 among pediatric patients aged 0-4 years. This figure also ranged from 140-725 among children aged 5-9 years during the same time period.

The monthly percentage of specimens positive for adenovirus types 40/41 ranged from 5-19% for individuals aged 0–4 years and from 3-14% among children aged 5–9 years between October-March 2017-2018, 2018-2019, and 2019-2020.

“After a decrease in testing volume and percentage positive during April 2020–September 2021, the percentage of specimens positive for adenovirus types 40/41 during October 2021–March 2022 returned to, but did not exceed, prepandemic levels in both age groups,” the authors wrote.

However, there are plans to continue to assess trends, as well as conduct enhanced epidemiologic investigations to help contextualize reported cases of acute hepatitis of unknown etiology in US children.

“Current data do not suggest an increase in pediatric hepatitis or adenovirus types 40/41 above pre–COVID-19 pandemic baseline levels; continued surveillance is important to monitor changes over time,” the authors wrote.

The study, “Trends in Acute Hepatitis of Unspecified Etiology and Adenovirus Stool Testing Results in Children—United States, 2017-2022,” was published online in the Morbidity and Mortality Weekly Report (MMWR).