Objective To understand the prevalence of hepatitis B virus (HBV) infection and the effectiveness of HBV vaccination among community residents in Shanghai city, and to provide scientific evidence for optimizing current HBV prevention and control strategies.

Methods Based on two-stage probability proportional to size (PPS) sampling, serological surveys of HBV were conducted among community residents aged 1–69 years in Shanghai city in 2018 and 2020. Basic information such as gender, age, household registration, and vaccination history were collected through questionnaires. Venous blood samples were collected for HBsAg, anti-HBs, and anti-HBc testing. For those aged 15–69 years who tested positive for HBsAg in the 2020 survey, further clinical examinations were conducted to assess whether they were HBV carriers, chronic hepatitis B patients, or cirrhosis patients. Based on population size and age structure, complex sampling weights were applied to adjust the survey data. Rao-Scott χ² tests were used for intergroup comparisons.

Results A total of 5 523 community residents in Shanghai city were included in this study. The positive rates of HBsAg, anti-HBs, and anti-HBc were 3.95%, 48.06%, and 32.69%, respectively. The positive rates of HBsAg and anti-HBc in the 5–29 age group were significantly lower than those in the 30–69 age group (Rao-Scott χ² = 20.20 and 179.24, respectively, both P < 0.0001), and significantly higher than those in the 1–4 age group (Rao-Scott χ² = 17.99 and 18.58, respectively, both P < 0.0001). The positive rate of anti-HBs in the 5–29 age group was significantly lower than that in the 1–4 age group (Rao-Scott χ² = 60.86, P < 0.0001). The positive rates of HBsAg and anti-HBc in the central urban area were significantly higher than those in the suburbs (Rao-Scott χ² = 38.26 and 11.12, respectively, both P < 0.001). The positive rate of anti-HBs in the registered population was significantly lower than that in the non-registered population (Rao-Scott χ² = 135.75, P < 0.0001). The infection risk among community residents has decreased significantly compared with previous years, and the infected population is mainly concentrated in those aged ≥ 40 years. Among community residents, the previous HBV vaccination rate was 32.95%. The positive rates of HBsAg and anti-HBc in vaccinated individuals were significantly lower than those in unvaccinated individuals (Rao-Scott χ² = 9.75 and 22.22, respectively, P < 0.01 and P < 0.0001, respectively), while the positive rate of anti-HBs was significantly higher in vaccinated individuals than in unvaccinated individuals (Rao-Scott χ² = 565.76, P < 0.0001). This survey also identified 16 suspected cases of early acute HBV infection, with an infection rate of 0.38%. Among the 27 HBsAg-positive individuals who underwent further clinical examination in 2020, HBV carriers accounted for 70.37%, chronic hepatitis B patients accounted for 14.81%, and cirrhosis patients accounted for 3.70%.

Conclusions The HBsAg positive rate among community residents in Shanghai city has decreased from 6.78% in 1992 to 3.95% in 2018–2020. The HBsAg positive rate in children under 5 years old has approached the WHO target. Shanghai city is transitioning from an intermediate HBV endemic area to a low endemic area. It is recommended that, on the basis of continuing to strengthen HBV vaccination for newborns, vaccination for high-risk groups and antiviral treatment for HBV-infected individuals should be carried out in conjunction with surveillance efforts to contribute to the elimination of HBV.