Determinants of uptake of third doses of oral polio and DTP vaccines in the Ibadan North Local Government Area of Nigeria.

Background: High dropout rates in the uptake of oral polio vaccine (OPV) and DTP vaccine persist despite efforts to improve immunisation coverage. This study identified determinants of uptake of third doses of OPV3 and DTP3 among infants who received first doses of either or both vaccines at immunisation centres in the Ibadan North Local Government Area of Nigeria.

Methods: Using a cohort study design, 400 mother-child pairs were assessed. A semi-structured, interviewer-administered questionnaire was used to collect data from each participant who were followed up for 90 days. Dates of subsequent doses of the vaccines were recorded. Multivariate analysis was performed using the log-rank test and Cox's regression analysis to identify predictive factors.

Results: Only 43.5% (174/400) and 24.8% (89/359) of children completed the OPV3 and DTP3 vaccines, respectively. Factors predictive of uptake of OPV3 were first birth (HR=1.66, 95% CI 1.11-2.48) and attending a tertiary health facility (HR=2.27, 95% CI 1.41-3.65), while attending a secondary health facility was significant for DTP3 uptake (HR=2.43, 95% CI 1.30-4.61).

Conclusions: Uptake of third doses of vaccines was influenced by the type of health facility attended and the child birth order. Efforts to reduce vaccination dropouts should include creation of awareness of the importance of completing immunisation schedules for children of higher birth orders as well as improved service delivery at health facilities.