Community resilience of community-based organizations and performance of the expanded programme on immunization in Richard toll, Sénégal

Routine immunization remains a public health priority in Senegal, where incomplete vaccination, schedule discontinuation, and territorial inequalities persist. Community-based organizations (CBOs) may help bridge households and health services through social mobilization, active case finding, referral, and follow-up. Objective: To assess the level of CBO engagement and describe concurrent changes in key Expanded Programme on Immunization (EPI) indicators in the Thiabakh Health Centre catchment area of the Richard-Toll Health District.  A descriptive observational study combined a cross-sectional survey of CBO members with a retrospective analysis of aggregated EPI indicators. Seven of nine available CBOs were included, with five purposively selected members per organization (n = 35). Data were collected over 21 days using a questionnaire, an interview guide, and routine programme records. June and December 2024 indicator values were compared descriptively.  Women represented 85.7% of participants. Reported participation in social mobilization was 94.3%, and involvement in vaccination sessions was 97%. Between the end of June and the end of December 2024, BCG/Penta 1 coverage increased from 55% to 85%, Penta 3 completion increased from 60% to 81%, the dropout indicator decreased from 40% to 12%, and recruitment of zero-dose children increased from 25% to 68%.  High reported CBO engagement coincided with favourable changes in routine immunization indicators. Because the study lacked a comparison group and used aggregated data, the findings indicate temporal association rather than causal effect. Formalized roles, supportive supervision, simple tracking systems, and stronger prospective evaluation are recommended.