Epidemiological characteristics and spatiotemporal clustering of hepatitis E in Zhejiang Province, 2008-2023

Objective: To understand the epidemiological characteristics and spatiotemporal distribution of hepatitis E in Zhejiang Province from 2008 to 2023 and provide scientific evidence for the prevention and control of hepatitis E.

Methods: The incidence data of hepatitis E in Zhejiang from 2008 to 2023 were obtained from China Disease Control and Prevention Information System. Joinpoint regression model was used to analyze the trends in incidence rates. Software ArcGIS 10.8 was used to analyze the spatial distribution and autocorrelation of hepatitis E cases, while software SaTScan 10.1 was used to investigate spatial clustering at district level.

Results: A total of 33 027 cases of hepatitis E were reported in Zhejiang from 2008 to 2023. The average annual incidence rate was 3.64/100 000. The majority of the cases reported were men (21 739), and higher average annual incidence rate was observed in the age group 50-74 years (32.04/100 000). The overall reported incidence rate declined first and then increased in 2020, showing a seasonal distribution with a high incidence from January to May. Notably, the incidence was particularly high in Hangzhou (6.54/100 000) and Quzhou (5.56/100 000). Spatial autocorrelation analyses revealed that the incidence of hepatitis E exhibited high-high clustering in all the years, with northwestern Zhejiang as main affected area. Prior to 2020, the high-high clustering area in northwestern Zhejiang became smaller, followed by an expansion trend in 2020-2022. Spatiotemporal clustering analyses identified seven clustering areas from 2010 to 2019, one was in 16 counties (cities, districts) in northwestern Zhejiang. And the clustering areas along the coastline shifted from the north to the south.

Conclusions: The incidence of hepatitis E in Zhejiang exhibited distinct spatiotemporal clustering pattern. Consequently, targeted prevention and control measures could be taken for hepatitis E in high-risk areas in Zhejiang, including northwestern and coastal areas.