Unveiling and addressing implementation barriers to routine immunization in the peri-urban slums of Karachi, Pakistan: a mixed-methods study

Abstract Background Great disparities in immunization coverage exist Pakistan between urban and rural areas. However, estimates for large peri-urban slums Sindh are largely unknown implementation challenges remain unexplored. This study explores key supply- demand-side barriers slums, as well strategies to address them. It also assesses the target slums. Methods Conducted four Karachi, this mixed-methods consists of a baseline cross-sectional survey representative sample 840 caregivers children aged 12–23 months, 155 in-depth interviews (IDIs) through purposive sampling respondents (caregivers, community influencers staff). After identifying barriers, further six IDIs were then conducted with policy-makers policy determine these resulting development an original validated framework A thematic analysis approach was applied qualitative data. Results The revealed 49% fully vaccinated, 43% partially vaccinated 8% unvaccinated. Demand-side included household lack knowledge awareness, misconceptions fears regarding vaccines social religious barriers. Supply-side underperformance staff, inefficient utilization funds, unreliable data interference polio campaigns immunization. framework’s recommendations include: (1) improved human resource management; (2) staff training on counselling; (3) re-allocation funds towards incentives, outreach, salaries infrastructure; (4) digital platform integrating birth registry vaccination tracking systems monitoring reporting by frontline staff; (5) use targets generating dose reminders; (6) mutual sharing resources immunization, Lady Health Worker programmes coverage. Conclusions is underpinned uncharted complex can be used implementers other developing countries improve limited-resource settings, possible application at larger scale. In particular, expanded nationwide use.