Last year, health experts worldwide were puzzled by reports of severe, unexplained hepatitis in previously healthy children. A recent study conducted by the University of California, San Francisco (UCSF) has shed light on this mysterious outbreak of acute severe hepatitis that affected children in the United States and 34 other countries in spring 2022.
With around 1,000 cases reported, 50 children required liver transplants, and at least 22 died.
The researchers discovered that the disease was linked to co-infections from multiple common viruses, particularly adeno-associated virus type 2 (AAV2), which alone does not cause hepatitis. AAV2 needs “helper” viruses, such as adenoviruses responsible for colds and flus, to replicate in the liver. When children returned to school after COVID-19 lockdowns, they became more vulnerable to infections from these common pathogens. For a small group of these children, getting more than one infection simultaneously made them more susceptible to severe hepatitis.
The research was published in the journal Nature alongside two British studies that also implicated AAV2 in hepatitis cases. These consistent findings were considered “quite striking” by Dr. Frank Tacke, a gastroenterologist not involved in the research. However, uncertainties remain regarding how these infections might trigger hepatitis and whether AAV2 plays a causal role or is merely a bystander.
The timing of the outbreak might be related to the loosening of pandemic precautions, leaving large numbers of young children exposed to common viruses they had not previously encountered. βIt may have resulted in a population that was highly vulnerable to getting infected with multiple viral infections,β said Dr. Charles Chiu, an author of the study.
The researchers used polymerase chain reaction (PCR) and metagenomic sequencing to examine samples from 16 pediatric cases in six U.S. states and compared them with 113 control samples. They detected AAV2 in 93% of the cases, along with human adenoviruses and co-infections with Epstein-Barr, herpes, and enterovirus in 85.7% of cases.
More research is needed to establish a direct causal link between AAV2 and severe acute hepatitis. However, the findings suggest that co-infections may trigger more severe hepatitis, especially in young children whose immune systems were not exposed to pathogens due to lockdowns. Although the cases of acute severe hepatitis in children have declined, frequent handwashing and staying home when sick are advised to protect children from developing this debilitating disease.
Key Takeaways in a Nutshell – Health Newstrack
– A mysterious outbreak of acute severe hepatitis affected previously healthy children in the United States and 34 other countries in spring 2022, with around 1,000 cases reported, 50 children requiring liver transplants, and at least 22 deaths.
– Recent research suggests the disease is linked to co-infections from multiple common viruses, particularly adeno-associated virus type 2 (AAV2), which alone does not cause hepatitis but needs “helper” viruses to replicate in the liver.
– The timing of the outbreak may be related to the loosening of COVID-19 pandemic precautions, leaving young children exposed to common viruses they had not previously encountered.
– Uncertainties remain regarding how these infections might trigger hepatitis and whether AAV2 plays a causal role or is merely a bystander.
– More research is needed to establish a direct causal link between AAV2 and severe acute hepatitis, but co-infections may trigger more severe hepatitis in vulnerable young children with untrained immune systems due to lockdowns.