Impact of COVID-19 on routine immunization in Oyo State, Nigeria: trend analysis of immunization data in the pre- and post-index case period; 2019-2020.

Introduction: the response to COVID-19 pandemic has posed new obstacles to the fragile health system, most especially in the area of vaccination across much of Africa. As the response to the pandemic intensifies through the application of non-pharmacologic interventions as well as enforcement of the lockdowns across African cities, there is a significant risk that more children will miss out on life-saving vaccines that can prevent childhood killer diseases. This study was therefore conducted to look at the impact of the COVID-19 pandemic on routine immunization in Oyo State, Nigeria.

Methods: we conducted a descriptive secondary analysis of immunization data between July 2019 and August 2020. These data were retrieved from the monitoring and evaluation unit of Oyo State Primary Health Care Board. The data were extracted from the original paper format and entered into Excel sheets. Line graphs were plotted to compare the trends of the coverage rates before and after the index case of the COVID-19 pandemic.

Results: the average coverage rates for Bacillus Calmette-Guérin (BCG) before and after index case were 85.8% and 82.1% respectively, while it was 63.5% and 60.0% for HBV0. For the co-administered vaccines at 14 weeks, Penta 3, OPV 3, PCV 3 and IPV coverage rates dropped from 76.1%, 75.4%, 75.1% and 73.5% to 72.0%, 71.4%, 72.0% and 71.9% respectively. The average coverage rates for yellow fever and measles dropped sharply from 77.0% and 74.5% and 64.6% and 58.6% respectively. The average drop-out rates for the pre-and post-index case periods were 5.0% and 4.7% respectively. For the planned fixed and outreach sessions, none of the monthly sessions met the target of 100.0% in the post-index case period.

Conclusion: decreased vaccination coverage for vaccine-preventable diseases could cause parallel outbreaks with COVID-19 and further exacerbate the strain on health systems attempting to end the acute phase of this pandemic. Therefore, as the dramatic second wave unfolds, the Government of Nigeria must take deliberate steps to strike a balance between a fresh lockdown and the imperative of uninterrupted social service. In this wise, it must remain committed to a timely vaccination program.