Objective To analyze the reported‑case characteristics and incidence of hepatitis A in Yuxi City of Yunnan Province before (1994‒2008) and after (2009‒2023) the live attenuated hepatitis A vaccine was incorporated into the expanded program on immunization (EPI), to provide a basis for formulating hepatitis A prevention and control strategies.

Methods Data on reported hepatitis A cases in Yuxi City of Yunnan Province from 1994 to 2023 were collected from the Yuxi City Epidemic Data Compilation and the China Disease Surveillance Information Reporting Management System. Descriptive epidemiological analyses were used to characterize age distribution, occupational composition, and incidence rates across different time periods, genders, and region of the reported hepatitis A cases in Yuxi City from 1994 to 2023 as well as before and after the EPI. Concentration ratio (M) analysis methods were employed to analyze the seasonality of hepatitis A incidence.

Results From 1994 to 2023, a total of 6 028 cases of hepatitis A were reported in Yuxi City. Hepatitis A cases were reported across all age groups, with the proportion of cases decreasing as age increased. After the implementation of the EPI, the highest proportion of cases was observed in the 30 to under 45 years old age group (26.48%). Before the EPI, students constituted the majority of hepatitis A cases (37.20%), while after the EPI, farmers became the predominant group (48.73%). From 1994 to 2023, the average annual reported incidence rate of hepatitis A in Yuxi City was 9.75/100 000. The overall reported incidence rate showed a declining trend year by year (χ²_Trend=3 566.82, P<0.001), with the average annual reported incidence decreasing from 16.78/100 000 before the EPI to 2.72/100 000 after the EPI. The seasonality of hepatitis A incidence was not pronounced (1994‒2023: M=0.184; pre-EPI: M=0.207; post-EPI: M=0.059). The reported incidence rate was higher in males (11.47/100 000) than that in females (7.98/100 000). From 1994 to 2023, the top three counties (cities and districts) in Yuxi City with the highest cumulative reported incidence rates were Tonghai County (18.41/100 000), Eshan Yi Autonomous County (15.42/100 000), and Jiangchuan District (10.34/100 000). After the EPI, the reported incidence rates of hepatitis A declined significantly across all regions, with the average reported incidence rate dropping from 17.50/100 000 to 2.31/100 000. Based on gross domestic product (GDP) levels, the nine counties (cities and districts) of Yuxi City were categorized into three types of regions, and the reported incidence rate of hepatitis A decreased as the regional GDP level increased.

Conclusion Following the inclusion of hepatitis A vaccines in the EPI in Yuxi City, the reported incidence rate of hepatitis A declined. Farmers and individuals aged 30 to under 45 years old constituted higher proportions of hepatitis A cases. Men were the key population for hepatitis A prevention and control, while regions with lower GDP levels were the priority areas for hepatitis A interventions. It is recommended to further expand vaccine coverage in these key regions and among key populations, while simultaneously strengthening health education and environmental improvements to consolidate prevention outcomes and abbreviate regional incidence disparities.