Hepatitis B virus infection among 90 million pregnant women in 2853 Chinese counties, 2015-2020: a national observational study

China has the largest disease burden of hepatitis B virus (HBV) infection and is considered as a major contributor to the global elimination of hepatitis B by 2030. However, the national prevalence of HBV infection among Chinese pregnant women was not reported yet. We evaluated the national and regional prevalence of HBV infection among pregnant women in China between 2015-2020, aiming to provide the latest baseline data.We assessed the prevalence of HBV infection from data gathered through a nationwide cross-sectional study of Chinese pregnant women. Data were obtained from the National Integrated Prevention of Mother-to-Child Transmission of HIV, Syphilis and Hepatitis B Programme (iPMTCT Programme) in China, which covered all the 2856 counties from 31 provinces from 2015 to 2020. HBV infection was defined as being tested seropositive for hepatitis B surface antigen (HBsAg).A total of 90.87 million pregnant women in mainland China were testing for HBV between 2015 and 2020, with 5.60 million (6.17%, 95%CI: 6.16-6.18%) tested positive for HBsAg. From 2015 to 2020, the prevalence of HBV infection among pregnant women declined by 25.44%, from 7.30% in 2015 to 5.44% in 2020 (p for trend < 0.001), with an estimated annual percentage change (EAPC) of -5.27% (95% CI: -3.19% to -7.32%). Compared with the prevalence in 2015, reginal disparities in eastern, central, and western China were narrowed. Declines were also observed at provincial level and county level. HBV prevalence declined in most provinces (90.3%, 28/31) and counties (76.96%, 2198/2856) from 2015 to 2020. However, disparities still exist.HBV prevalence in pregnant women in China was intermediate endemic and declined continuously from 2015 to 2020. The decline has been widespread across regions, but disparities remain. Regions with relatively higher disease burden on HBV infection should receive most attention in achieving the 2030 elimination goals.National Natural Science Foundation of China.