Childhood Virus AAV2 Linked to Acute Unexplained Hepatitis in New Study

A new study published in the journal Nature has found that a common childhood virus, adeno-associated virus type 2 (AAV2), is present in a range of different samples taken from children with acute unexplained hepatitis. The study was led by researchers at the University of Glasgow and analysed blood, stool and liver biopsies from 16 children in the US with severe hepatitis. AAV2 was detected in 93% of samples in patients with hepatitis, compared to only 3.5% of control participants. In addition, the scientists detected the existence of other viral infections among individuals with hepatitis.[0]

While AAVs are not considered pathogenic on their own, more research is needed to establish a direct causal link with the severe acute hepatitis. The results indicate that co-infections could lead to more severe hepatitis, particularly in susceptible young children whose immune systems did not receive their usual “training” from frequent exposure to pathogens during lockdowns.[1] Although adeno-associated virus infections can occur in individuals of all ages, the majority of cases are found in children between the ages of 1 and 5, with the average age of affected children being three years old.[2]

Since AAV2 is not considered pathogenic on its own, a direct causal link with the severe acute hepatitis has yet to be established. However, the study notes that children may be especially vulnerable to more severe hepatitis triggered by co-infections.[3] Health experts have been puzzled after over 1,000 children around the world were diagnosed with cases of hepatitis starting in 2021.[4] Almost 400 cases of hepatitis among children in the United States remain unexplained.[4] As per the Centers for Disease Control and Prevention, 22 youngsters underwent liver transplants, and 13 passed away.[4]

“The presence of the AAV2 virus is associated with unexplained hepatitis in children,” said Prof Emma Thomson, clinical professor and consultant in Infectious Diseases at the MRC-University of Glasgow Centre for Virus Research (CVR) and senior author of the study. “We were surprised by the fact that the infections we detected in these children were caused not by an unusual, emerging virus, but by common childhood viral pathogens,” said Dr Charles Chiu, professor of laboratory medicine and medicine at the University of California, San Francisco, and senior author of the paper.[5]

Chiu noted that the results also mirrored the findings of two concurrent studies conducted in the United Kingdom, which identified the same AAV2 strain.[6] Although the clusters of acute severe hepatitis in children have decreased in recent times, Chiu advised that the most effective measure to prevent such an unexpected event is by practicing frequent hand washing and staying at home when feeling unwell. Although there has been a decrease in the number of acute severe hepatitis cases in children, Chiu suggests that the most effective way to safeguard children from this condition in the future is by promoting good hand hygiene and encouraging sick individuals to stay home, which can help prevent the spread of common childhood infections.

In October 2021, the initial instances of the hepatitis outbreak were documented in Alabama.[7] Despite testing negative for the prevalent hepatitis A, B and C viruses, five children had severe liver diseases, including liver failure. As per the CDC, they were diagnosed with adenovirus, a prevalent virus that usually results in symptoms similar to cold and flu, and in rare cases, can also lead to stomach and intestinal issues.[8] Children who had returned to school were more susceptible to these severe infections, leading researchers to speculate that the outbreak was related to COVID-19 related school and daycare closures and social restrictions.[9]

0. “Common viruses may be reason for hepatitis cases in children, researchers find” Sky News, 31 Mar. 2023,

1. “Severe hepatitis outbreak linked to common viruses”, 30 Mar. 2023,

2. “Almost 93% Of Pediatric Hepatitis Cases Found To Share A Common Factor” Revyuh, 30 Mar. 2023,

3. “Severe hepatitis outbreak linked to common childhood viruses” Medical Xpress, 30 Mar. 2023,

4. “Scientists Discover Possible Cause Of Mysterious Liver Disease In Children” iHeartRadio, 31 Mar. 2023,

5. “Research points to common infections as cause of liver disease outbreak in kids” KAKE, 31 Mar. 2023,

6. “New Clues to Recent Hepatitis Outbreak in Kids” The Killeen Daily Herald, 31 Mar. 2023,

7. “Studies Shed Light On Rare Hepatitis That Sickened CT Children”, 31 Mar. 2023,

8. “Studies Shed Light On Puzzling Severe Hepatitis Outbreak In Young Kids” Patch, 31 Mar. 2023,

9. “What's causing the surge of hepatitis in young children?” KPVI News 6, 30 Mar. 2023,

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