The effect of the COVID-19 pandemic on routine childhood immunization coverage and dropout: A community-based cross-sectional study in the Tamale Metropolis, Ghana

BACKGROUND: The COVID-19 pandemic disrupted essential health services globally, including routine childhood immunization. However, the extent to which these disruptions affected different points along the immunization schedule remains unclear. This study examined the impact of the pandemic on vaccination coverage, dropout rates, and reasons for incomplete age-appropriate immunization in the Tamale Metropolis, Ghana. METHODS: A community-based cross-sectional study was conducted among 1501 caregivers of children aged 0-59 months from November 2022 to January 2023, using a multistage cluster sampling technique. Children were categorized as pre-pandemic birth cohort (those who were eligible for vaccines before 12th March 2020, the date of the first confirmed COVID-19 case in Ghana), mid-pandemic birth cohort (those who were eligible for vaccine from 12th March 2020 to 11th March 2021) and post-pandemic birth cohort (those who were eligible for vaccine from 12th March 2021 to 17th December 2022). All estimates were generated using design-based analysis to account for the survey design. We present coverage and dropout estimates for Bacillus Calmette-Guérin (BCG), pentavalent (Penta1 and Penta3), and measles-rubella (MR1 and MR2) vaccines. RESULTS: Coverage for early vaccines remained relatively stable across cohorts, with BCG declining slightly from 81.3% in the pre-COVID birth cohort to 80.6% in the mid-COVID birth cohort but rebounded to 88.8% in the post-COVID birth cohort. Penta1 coverage remained consistently high (>91%) across cohorts. In contrast, coverage for later-scheduled vaccines declined across cohorts. Penta3 coverage decreased from 88.2% in the pre-COVID birth cohort to 87.8% in the mid-COVID birth cohort, and further to 81.7% in the post-COVID birth cohort. Similarly, MR2 coverage declined from 48.5% in the pre-COVID birth cohort to 25.8% in the post-COVID birth cohort. Penta1-Penta3 dropout increased marginally from 4.1% in pre-COVID birth cohort to 4.2% in the mid-COVID birth cohort and substantially to 14.4% in the post-COVID birth cohort. Penta3-MR1 dropout nearly doubled in the post-COVID birth cohort (20.8%) compared to pre-COVID birth cohort (12.0%). CONCLUSION: Early immunization contacts in Tamale remained resilient during COVID-19, but continuity across the vaccination schedule weakened, particularly for later doses. Strengthening defaulter tracing, caregiver counselling, and vaccine supply continuity is essential to restore full schedule completion and improve resilience against future disruptions.