Risk Factors of Incomplete Immunization Among Children Under Five in Nigeria: An Analysis of theDemographic Health Survey

BACKGROUND: Nigeria is among the countries with the lowest immunization coverage in the AFRO region according to the WHO estimates. In 2018, 70% of the population is not vaccinated, representing an approximated 3 million people. Incomplete or inexistent vaccination is due to multiple factors pertaining to the health system, family factors, available information, and communication strategies. This multilevel aspect of the risk factors was identified in a systematic review that focused on low and middle-income countries suggesting that social determinants of health have an impact on the immunization coverage. The present thesis focused on the individual, family, and community socio-economic factors that influence incomplete immunization in Nigeria. METHODS: Data from the Demographic and Health Survey (DHS) datasets made publicly available by USAID (DHS program, available datasets, 2009 -2018) were used to conduct a cross-sectional analysis. Factors were categorized into individual-, family-, and community-levels. We focused on the following vaccines’ coverage status: BCG, Pentavalent, Polio 3, and Measles. The data analysis was performed using SAS software to run a multilevel model. We also used ArcMap to perform a spatial analysis of the immunization coverage rates in the country. RESULTS: We identified risk factors such as lack of access to prenatal care, home delivery, lack of access to media outlets, the lack of mothers education, and the low economic status that influence incomplete immunization in Nigeria in children aged between 12 – 23 months old. This study also showed the increased influence of family and community factors on immunization coverage, in accordance with the Social Determinants of Health concept. CONCLUSION: Interventions that aim to increase the uptake of child immunization should focus on these factors and act on three axes: a policy, research, and health systems strengthening components