Evaluation of the effect of enhanced immunization in adults: A cross-sectional study in the southeast city of China.

The efficacy of hepatitis B vaccination in adults was evaluated by comparison of the positive seroprotection rates and the hepatitis B surface antibody (anti-HBs) geometric mean titers (GMTs) between intensive intervention areas and non-intensive intervention areas after 8 years post-vaccination in the Zhejiang province. Seven cities (towns) in Zhejiang province were selected as intensive intervention areas, and adults in the demonstration areas receive hepatitis B vaccine voluntarily and for free. Other areas were non-intensive intervention areas. A total of 3587 participants received the full vaccination course (three doses), and blood samples were withdrawn 8 years after the first vaccination comprised the immunized group, and 2000 participants constituted the control group. The anti-HBs positive seroprotection rates of the immunized and control groups were 65.0% and 53.0%, respectively. The anti-HBs GMT of the subjects in the immunized group was 26.30 mIU/mL compared to 9.33 mIU/mL in the control group ( P  < .001). Significant differences were detected in the 24-35-, 36-45-, and 46-55-year-old subgroups in the positive seroprotection rates and the anti-HBs GMTs ( P  < .001) between the immunized and control groups. Moreover, significant differences were found in the anti-HBs GMT in the 46-55-year-old subgroup between the two groups ( P  = .02), while no differences were observed in the positive seroprotection rate ( P  = .428). In conclusion, adults who did not receive the hepatitis B vaccine in infancy and had negative serological markers of hepatitis B, especially adults <47-years-old, need vaccination.