Reprint of: Factors associated with effectiveness of the first dose of hepatitis B vaccine in China: 1992-2005.

Background: In China, the prevalence of chronic hepatitis B infection was high because of perinatal and early childhood transmission. A three-dose hepatitis B vaccine schedule with a first dose as soon as possible after birth was introduced in 1992 and generalized in 2002 in the Expanded Programme of Immunization (EPI). In 2006, a serological survey evaluated the effectiveness of vaccination.

Methods: We conducted a restricted analysis of the national serological survey that sampled children and collected information on demographic characteristics, birth history, hepatitis B vaccination and hepatitis B surface antigen (HBsAg) status as determined by ELISA testing. We compared children who received the first dose in a timely way (i.e., within 24h of birth) with others in terms of HBsAg status, stratified by birth cohort and place of birth.

Results: Three-dose hepatitis B vaccine coverage increased from 60.8% for children born in 1992-1997 to 93.2% for children born in 2002-2005. Meanwhile, timely birth dose coverage increased from 38.7% to 74.4%. Among 29,410 children born in 1992-2005 who had received three vaccine doses and no hepatitis B immune globulin, factors associated with being HBsAg-negative in multivariate analysis included receiving a timely birth dose (p=0.04), birth after 1998 (p<0.001), living in an urban setting (p=0.008) and hospital birth (p=0.001). The relative prevalence of HBsAg among children receiving the timely birth dose was lower for children born in county or larger hospitals (0.39), intermediate in township hospitals (0.73) and highest at home (0.87).

Conclusions: Hospital birth and receiving a timely birth dose are the main determinants of the field effectiveness of the first dose of hepatitis B vaccine. Efforts to increase the proportion of hospital deliveries are key to increasing timely birth dose coverage and its effectiveness.