Significant gaps in hepatitis B vaccination in adults in Viet Nam: Important targets toward hepatitis B elimination by 2030

•A significant unmet need for hepatitis B vaccination in adults remained in Viet Nam.•More people in the young age groups should be recommended for hepatitis B vaccination.•The social disparity in hepatitis B vaccination existed in various socioeconomic statuses.•Hepatitis B vaccination should be recommended for the broader population to achieve elimination.