Impact of Enhanced Outreach Activities on Immunization Coverage in Pakistan: Evidence from Secondary Data Analysis (2011-2021).

BACKGROUND: Despite noteworthy progress in the Expanded Program on Immunization (EPI) for improving vaccination coverage worldwide, inequalities in vaccine uptake and accessibility persist in several middle- and low-income states. Pakistan's routine vaccination uptake varies greatly between federal geographical regions and continues to fall below the standard threshold needed to attain optimal herd immunity. The Federal Directorate of Immunization (FDI) in collaboration with the provincial Expanded Program on Immunizations implemented Enhanced Outreach Activities (EOAs) to boost immunization delivery in selected districts in order to address immunization coverage gaps in marginalized and difficult-to-reach communities. The purpose of this secondary data research was to evaluate whether EOAs improved immunization coverage in the country.

METHODS: The Federal Directorate of Immunization's longitudinal panel analysis of district-month administrative data for the years 2011-2021 have been analyzed. The research investigation reviewed 158 districts' monthly vaccination records for multiple antigens, covering regions where EOAs were successfully carried out in particular months. National and subnational analyses were carried out to measure geographical variations in the impact of Enhanced Outreach Activities (EOAs). The average vaccination coverage during EOAs and non-EOAs months was compared using the paired t-test.

RESULTS: An aggregate of 2430 months with EOAs were included in the analysis of 19,068 monthly district observations. National level analysis revealed higher average vaccinations during the EOA months for all antigens, but a statistically significant increase was observed for IPV and measles second dose (p < 0.05) only. Provincial-level results indicate that the impact was more evident in underserved regions. Khyber Pakhtunkhwa, Balochistan, Punjab, and Sindh demonstrated statistically significant increases in vaccination counts for most antigens. Due to variations in baseline population coverage, as well as health care sector capability, the extent of improvements differed throughout regions.

CONCLUSIONS: In Pakistan, routine immunization counts has been improved via enhanced outreach initiatives, especially in provinces with lower initial vaccination rates and restricted accessibility to services. Strengthening outreach strategies, together with consistent fixed-site immunization services, is likely to accelerate progress toward equitable immunization coverage and contribute to achieving the Immunization Agenda 2030 goals.