Abstract
BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic disrupted essential health care services worldwide, including those related to immunisation. National data from Bangladesh shows that child immunisation may have been adversely affected by the pandemic but regional evidence is limited. We therefore aimed to explore the regional differences in the indirect effects of COVID-19 on child immunisation in Bangladesh. METHODS: We extracted data from the District Health Information Software (DHIS2) spanning the period from January 2017 to December 2021. We examined three essential immunisation indicators: Bacille Calmette-Guérin (BCG), pentavalent third dose, and measles vaccinations. We examined both the yearly and monthly trends to explore fluctuations in the number of immunisations to pinpoint specific periods of service utilisation regression. Segmented regression with Poisson distribution was implemented given the count-based outcome. We reported incidence rate ratios (IRRs) with 95% confidence intervals (CIs) in different regions in 2020 and 2021 compared to the reference period (2017-19). RESULTS: We initially observed a notable decline in vaccine administration in April 2020 compared to the pre-pandemic period of 2017-19 with a drop of approximately 53% for BCG vaccines, 55% for pentavalent third doses, and 51% for measles vaccines followed by May 2020. The second half of 2020 saw an increase in vaccination numbers. There were noticeable regional disparities, with Sylhet (IRR = 0.75; 95% CI = 0.67-0.84 for pentavalent administration, IRR = 0.79; 95% CI = 0.71-0.88 for measles administration) and Chattogram (IRR = 0.77; 95% CI = 0.72-0.83 for BCG administration) experiencing the most significant reductions in 2020. In April 2020, Dhaka also experienced the largest decline of 67% in measles vaccination. In 2021, most divisions experienced a rebound in BCG and pentavalent administration, exceeding 2019 levels, except for Chittagong, where numbers continued to decline, falling below the 2019 figure. CONCLUSIONS: Our findings highlight the impact of the COVID-19 pandemic on childhood immunisation across regions in Bangladesh. Sylhet, Chattogram, and Dhaka divisions experienced the most significant reductions in immunisation services during 2020. This underscores the importance of targeted interventions and regional strategies to mitigate the indirect effects of future challenges on essential health care services, particularly childhood immunisation, in Bangladesh.