Analysis of the impact of COVID-19 pandemic and response on routine childhood vaccination coverage and equity in Northern Nigeria: a mixed methods study

Background Based on 2021 data, Nigeria had the second largest number of zero-dose children globally estimated at over 2.25 million, concentrated in the northern part of the country due to factors some of which are sociocultural. This study analysed the impact of the COVID-19 pandemic and response on childhood vaccination in Northern Nigeria.Methods Using a mixed methods sequential study design in the most populous northern states of Kaduna and Kano, quantitative routine immunisation data for the period 2018–2021 and qualitative data collected through 16 focus group discussions and 40 key informant interviews were used. An adaptation of the socioecological model was used as a conceptual framework. Mean vaccination coverages and test of statistical difference in childhood vaccination data were computed. Qualitative data were coded and analysed thematically.Results Mean Penta 1 coverage declined in Kaduna from 69.88% (SD=21.02) in 2018 to 59.54% (SD=19.14%) by 2021, contrasting with Kano where mean Penta 1 coverage increased from 51.87% (SD=12.61) to 56.32% (SD=17.62%) over the same period. Outreaches and vaccination in urban areas declined for Kaduna state by 10% over the pandemic period in contrast to Kano state where it showed a marginal increase. The two states combined had an estimated 25% of the country’s zero-dose burden in 2021. Lockdowns, lack of transport and no outreaches which varied across the states were some of the factors mentioned by participants to have negatively impacted childhood vaccination. Special vaccination outreaches were among the recommendations for ensuring continued vaccination through a future pandemic.Conclusion While further interrogating the accuracy of denominator estimates for the urban population, incorporating findings into pandemic preparedness and response will ensure uninterrupted childhood vaccination during emergencies. Addressing the identified issues will be critical to achieving and sustaining universal childhood vaccination in Nigeria