Hepatitis B vaccination among 1997-2011 birth cohorts in rural China: the potential for further catch-up vaccination and factors associated with infant coverage rates.

Hepatitis B vaccination rates in China have recently increased. This study aimed to investigate infant vaccination coverage for birth cohorts from 1997 to 2011 in rural regions and to assess catch-up vaccination potential. We used questionnaire-based interviews from a cross-section of 6,529 individuals from seven provinces. Logistic regression analyses were used to model two measures of infant vaccination status, namely, birth dose within 24 hours and three doses within the first year of life. During interviews, individuals' vaccination status and vaccination plan were recorded. Unvaccinated individuals without plans for future vaccination were presented with a hypothetical offer of free vaccination and indirect cost compensation. Institutional birth rates were higher than vaccination rates, but both increased over time. Vaccination coverage rates were not significantly associated with sex. Infant vaccination coverage was positively associated with a mother's educational level, household income level, knowledge of transmission routes, and perceived duration of protection obtained through vaccination. Vaccination status at the time of the survey showed the occurrence of catch-up vaccinations, but a notable percentage of individuals remained unvaccinated and had no plans for future vaccination. Of these individuals, approximately 50% were prepared to accept vaccination if offered free of charge.