Missed Opportunities for Childhood Immunization in Pakistan: Failure to Vaccinate Despite Health System Contact.

Despite global gains in vaccination coverage, Pakistan continues to lag in achieving universal immunization, with vaccine-preventable diseases (VPDs) contributing to approximately 15% of all deaths annually. We explored missed opportunities for vaccination (MOV) when eligible children failed to receive vaccines when their mothers visited healthcare facilities for unrelated medical needs. Secondary data analysis was conducted using the Pakistan Social and Living Standards Measurement Survey (PSLM) 2019-20, comprising 195,000 households and 103,464 eligible children. MOV was defined as the failure to administer an age-appropriate dose of either pentavalent (Penta-1, 2, 3) or measles (Measles-1, 2) vaccines during a maternal health visit. Weighted multivariate binomial logistic regression was used to explore the association between maternal visits to private healthcare facilities and MOV, adjusting for sociodemographic variables. Geospatial analysis was used to visualize district-level disparities using ArcGIS. Approximately 25% of children aged 1-5 years missed at least one dose of pentavalent or measles vaccination with regional variations. The rates of missed doses were similar for the first, second, and third antigen doses. Rural areas, male children, and households with uneducated mothers had more missed vaccinations, while missed opportunities were more common when mothers visited private healthcare facilities, particularly in urban settings (adjusted Odds Ratio (OR): 1.563 for Penta-1, Confidence Interval (CI): 1.519-1.608) where the private sector predominates and because the public sector accounts for nearly all vaccinations. However, since nearly all vaccinations are in the public sector and the bulk of healthcare seeking is in the private sector, opportunities to vaccinate missed children are lost. Policy and technological solutions that can identify and refer to these children for vaccination can close the national gap in universal vaccination.