Epidemiology of hepatitis B in Fenghua district, Ningbo, Zhejiang, 1992−2022

Objective To analyze the epidemiological characteristics of hepatitis B in Fenghua district of Ningbo, Zhejiang province, from 1992 to 2022.

Methods The incidence data of hepatitis B reported in Fenghua from 1992 to 2004 were collected through the local annual report of infectious diseases and the incidence data of hepatitis B reported in Fenghua from 2005 to 2022 were collected through China Disease Prevention and Control Information System. Due to the adjustment of immunization strategies, descriptive epidemiological analyses on the incidence of hepatitis B in Fenghua during 1992−2001, 2002−2011 and 2012−2022 were carried out.

Results From 1992 to 2022, a total of 7 950 cases of hepatitis B were reported in Fenghua, with an average annual reported incidence rate of 51.04/100 000. Since 2010, no unclassified hepatitis B cases have been reported in Fenghua, in the reported cases, chronic hepatitis B cases accounted for 93.90%. The average annual incidence rates of hepatitis B in Fenghua during the three periods were 54.57/100 000, 46.51/100 000 and 52.04/100 000, respectively. The incidence rate showed downward trends in age groups 0–14 years and 15–29 years (Trend χ²=10.040, P=0.002; Trend χ²=19.960, P<0.001), while showed an upward trend in age group ≥60 years (Trend χ²=16.440, P<0.001). From 1992 to 2022, the average annual reported incidence rate of hepatitis B was significantly higher in men (73.35/100 000) than in women (27.92/100 000) (χ²=51.000, P<0.001). From 1992 to 2022, the average annual percentage change (AAPC) of standardized incidence rate of hepatitis B in age group 0–14 years was −10.92% (95%CI: −13.35% – −8.43%, P<0.001), and the average percentage change (APC) of standardized incidence rate of hepatitis B in age group 15–29 years was −4.13% (95%CI: −5.57% – −2.66%, P<0.001). The overall coverage rate of hepatitis B vaccine was 99.20% from 1992 to 2022.

Conclusion The reported incidence of hepatitis B was at a relatively high level in Fenghua from 1992 to 2022. From 2010 to 2020, the incidence of acute hepatitis B showed a downward trend, the majority of the hepatitis B cases were chronic ones. The reported incidence of hepatitis B dropped significantly in the population born after the implementation of the hepatitis B immunization strategy. It is necessary to maintain a high hepatitis B vaccination coverage rate and strengthen the prevention and control of hepatitis B in adults.