Assessing vaccination coverage quality in Jamaica during COVID-19 using vcqiR: insights from the 2022 MICS

This analysis aimed to identify the underlying causes of gaps in routine immunization coverage observed during the COVID-19 pandemic recovery phase by applying the open-source Vaccination Coverage Quality Indicators package in R (vcqiR), addressing limitations in Multiple Indicator Cluster Surveys (MICS) that often omit quality metrics based on detailed vaccination date analysis.

This secondary analysis examined vaccination doses and dates from the Jamaica 2022 MICS (MICS4), for 570 children ages 12-23 months and 24-35 months. Specific indicators included coverage, timeliness, dropouts, and missed opportunities for simultaneous vaccinations (MOSVs).

Vaccination coverage for first-year-of-life (1YL) doses exceeded 83% for both age cohorts. Coverage for MMR1 showed substantial catch-up from 12-23 months to 24-35 months, achieving the 95% target. However, MMR2 coverage lagged substantially (37.2% for 12-23 months and 61.9% for 24-35 months), indicating significant attrition in the second year of life. In the 12-23 month cohort, crude coverage of Penta3 was 89%, but only 70% had three valid doses. Most 1YL doses were administered in a timely manner (within 28 days), but premature administration was observed. MOSVs were negligible for 1YL doses but were frequent and mostly uncorrected for 18-month boosters, especially MMR2.

The findings complement the MICS4 report and confirm robust early infant immunization delivery but identify programmatic gaps in second year-of-life retention plus the need to strengthen adherence to minimum age interval rules. These results provide detailed evidence necessary to inform targeted interventions and guide the design of future coverage surveys.