Systematic review of social determinants of childhood immunisation in low- and middle-income countries and equity impact analysis of childhood vaccination coverage in Nigeria

BackgroundNigeria has a high proportion of the worlds underimmunised children. We estimated the inequities in childhood immunisation coverage associated with socioeconomic, geographic, maternal, child, and healthcare characteristics among children aged 12-23 months in Nigeria using a social determinants of health perspective. MethodsWe first conducted a systematic review focused on inequities in childhood immunisation in low- and middle-income countries to identify the social determinants of childhood immunisation. To identify inequities in basic vaccination coverage in Nigeria (1-dose BCG, 3-dose DTP-HepB-Hib (diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae type B), 3-dose polio, and 1-dose measles) of 6,059 children aged 12-23 months using the 2018 Nigeria Demographic and Health Survey, we conducted multiple logistic regression to analyse the association of basic vaccination with these determinants. ResultsWe identified social determinants of immunisation: household wealth, religion, and ethnicity (socioeconomic characteristics); region and place of residence (geographic characteristics); maternal age at birth, maternal education, and maternal household head status (maternal characteristics); sex of child, and birth order (child characteristics); antenatal care and birth setting (healthcare characteristics). While basic vaccination coverage was 31% (95% CI: 29-33), 19% (95% CI:18-21) of children aged 12-23 months had received none of the basic vaccines. After controlling for background characteristics, there was a significant increase in the odds of basic vaccination by household wealth, antenatal care, delivery in a health facility, maternal age and maternal education. Children of Fulani ethnicity in comparison to children of Igbo ethnicity had lower odds of receiving basic vaccinations. ConclusionsChildren from the poorest households, of Fulani ethnicity, who were born in home settings, and with young mothers with no formal education nor antenatal care, were associated with lower odds of basic vaccination in Nigeria. Basic vaccination coverage is below target levels for all groups and we recommend a proportionate universalism approach for addressing the immunisation barriers.