Proportion of children born to infected mothers at risk of contracting Hepatitis B, and associated risk factors for inadequate Hepatitis B Timely Birth Dose vaccination : Analysis of the São Tomé and Príncipe Demographic Health Survey Program data, 2008-2009.

Background The Hepatitis B Virus (HBV) is a blood-borne infection affecting around 2 billion people at any given time and is commonly transmitted through Mother to Child Transmission (MTCT). Preventative measures include vaccinations, particularly the timely Birth Dose (TBD) given within 24 hours of birth. Timing is crucial for the efficacy of the TBD, and is influenced by various factors. São Tomé and Príncipe is one of seven sub-Saharan African countries with a TBD policy. This study aims to observe the different proportions of children receiving adequate or inadequate vaccinations against HBV, as well as to analyse the risk factors that may lead to inadequate vaccination. Methods Secondary data from the São Tomé and Príncipe Demographic Health Survey from 2008-2009 was analysed in this study. Dose delays for all children and those at risk were described. An associative analysis looked at the potential risk factors for inadequate TBD vaccination. Results A high coverage rate for vaccinations was found (>85%), however, the majority were delayed, with only 1% and 4% on time, and mean a TBD administration of 2(SD±2) months after birth, in all children, versus children at risk. Children born to mothers with positive HBV status and low wealth were significantly more likely to receive the TBD on time. Conclusion The majority of vaccinations, including the TBD were inadequately administered, denoting a concern of transmission to children born at risk. Additionally, socioeconomic factors were found to be factors influencing the provision of the TB