Active surveillance of hepatitis E: a 10-year epidemiological analysis in a city in eastern China.

Hepatitis E virus (HEV) is an important cause of acute hepatitis, however, is highly neglected and largely underreported. This study aimed to describe the detailed epidemiology of hepatitis E (HE) through a 10-year surveillance. A community-based active hepatitis surveillance was conducted between November 2007 and October 2017 in 11 townships of Dongtai City in China, involving 355,673 residents. Serum samples were obtained from patients presenting with hepatitis symptoms for more than 3 days. Serum alanine aminotransferase (ALT) levels greater than 2.5 times the upper limit of normal (ULN) were considered acute hepatitis. Samples were subsequently tested for IgG and IgM anti-HEV antibodies, HEV RNA, and hepatitis B surface antigen (HBsAg). The data indicated the incidence of HE fluctuated downward from 2007 to 2017, with an average annual age-standardized incidence of 17.50 per 100,000, exceeding the 10.26 per 100,000 in the National Notifiable Disease Report System (NNDRS). The incidence was notably higher among males (20.95 per 100,000) and individuals aged 50-69 years (37.47 per 100,000). Genotype 4 (HEV-4) was the predominantly circulating genotype during the study period. Furthermore, the study revealed the incidence of hepatitis with HEV and hepatitis B virus (HBV) co-infection was 4.99 per 100,000. The active surveillance system identified a higher incidence of HE compared to NNDRS, with a decreased prevalence over a 10-year period. While efforts are still needed to prevent HE in high-risk populations, including individuals with hepatitis B and the elderly.