Infection with the omicron variant of the coronavirus may have a role in recent cases of severe acute hepatitis in children, according to new research presented at a health ministry panel meeting Wednesday.

Kyoto University professor Hiroshi Nishiura told the ministry’s coronavirus advisory board that countries with a large number of omicron infections such as Britain and the United States were also found to have reported a relatively higher number of childhood hepatitis cases.

According to the World Health Organization, 348 probable cases of unexplained hepatitis in children have been confirmed worldwide, with only six countries reporting more than five cases. Japan’s health ministry has identified seven domestic cases so far, while the U.S is currently investigating 109 child hepatitis cases of unknown origin, according to the Centers for Disease Control and Prevention.