A Scalable Polio-EPI Synergy Model for Urban Immunization: Coverage Gains Following Workforce Integration in Lahore,...

Area of Science:

• Public Health
• Epidemiology
• Global Health

Background:

• Urban areas in low- and middle-income countries (LMICs) often struggle with under-immunized children, despite higher overall vaccination rates than rural regions.
• Lahore, Pakistan, faced low routine immunization coverage (70% fully immunized in 2022), particularly in urban slums, necessitating innovative interventions.
• An intervention in 2023 leveraged the existing polio eradication workforce to identify and vaccinate children missing routine immunizations.

Purpose of the Study:

• To evaluate changes in routine immunization coverage in under-immunized urban populations in Lahore.
• To assess the impact of engaging polio campaign workers to support routine immunization services.

Main Methods:

• A pre-post evaluation design involving two cross-sectional household surveys (2022 baseline, 2023 follow-up) of children aged 12-23 months.
• Utilized a door-to-door outreach strategy by polio vaccination teams to record immunization status.
• Employed two-stage cluster sampling and WHO-standard methods, verifying vaccination status via cards or caregiver recall.

Main Results:

• Full immunization coverage increased from 69.8% to 85.1%, with significant improvements in Penta-3 (83.2% to 94.1%) and Measles-1 (76.9% to 92.1%) coverage.
• The proportion of unvaccinated children decreased from 3.3% to 0.3%, and partial immunization dropped from 26.9% to 14.5%.
• Improvements were observed across all socio-demographic groups, with a notable impact in peri-urban and low socio-economic clusters.

Conclusions:

• Routine immunization coverage in urban Lahore improved significantly between 2022 and 2023, coinciding with polio worker outreach and post-COVID-19 recovery.
• While the study design indicates a temporal association rather than definitive causality due to the lack of a control group.
• Integrating the polio program workforce into routine immunization presents a promising strategy for addressing immunization gaps in urban LMICs.