Kogiso T, et al. - Acute hepatitis A [AH (A)] incidence is declining due to improvements in hygiene, though cases of sporadic severe hepatitis are still reported, so researchers conducted this hospital-based retrospective study to evaluate the epidemiology of AH (A) in Japan. Participants in the study were 126 AH (A) patients. For this investigation, they compared patients diagnosed with AH (A) before 2001 (n=79) and after 2001 (n=47). According to results, the incidence of AH (A) peaked in 1990, 1999, and 2018. Recently, sexual transmission has been the cause of outbreaks and severe AH (A) cases. Findings suggested that sexual behavior and other sexual infections need to be examined.