Study of factors influencing hepatitis B immunization coverage in 1 to 8-years-old children in the Ouidah health district in Benin in 2007

Hepatitis B is a major public health problem in Africa. The estimated prevalence in Benin is between 5.2% and 8.3%. Since 1992, the WHO has recommended immunization of all children between 0 and 12-months-old all around the world. Benin has been vaccinating children from 0 to 11 months since 1999. The purpose of this study was to identify factors influencing hepatitis B immunization coverage in children from 1 to 8-years-old in the Ouidah health district. This descriptive and analytical cross sectional study was carried out from October 25 to 31, 2007. The primary study targets were children from 1 to 8 years. Secondary targets were mothers and healthcare workers. A three-degree cluster sampling technique was used. Hepatitis immunization coverage was 72.2% (95%CI, 65.4 - 78.3). The negative factor influencing coverage in children was age over 5 years reflecting the absence of catch-up sessions for untargeted children overlooked for hepatitis B immunization. The negative factor in mothers was age over 30 years pending multivariate analysis that was not performed in this study. Regarding healthcare workers, understaffing was noted at this level of the health system. Hepatitis B immunization coverage in untargeted children was lower than in children between 0 and 11 months. In 2007, hepatitis B immunization coverage in the Ouidah health district was lower in untargeted children than children of 0 to 11 months. This study showed that immunization coverage decreased with age, thus underlining the need for catch-up sessions to ensure hepatitis B immunization in high prevalence areas.