Improving HPV Immunization Coverage Among Adolescent Girls in Mali and Côte d'Ivoire Through an Innovative Community-Based Follow-Up: A Randomized Controlled Trial With a Waitlist Design

Human papillomavirus (HPV) vaccination is one of the most effective strategies for preventing cervical cancer, yet coverage among adolescent girls in West Africa, including Mali and Côte d'Ivoire, remains far below the World Health Organization (WHO) target of 90% coverage by age 15. Barriers include limited community awareness, weak follow-up systems, and sociocultural constraints that contribute to missed vaccination opportunities. Muso Health has previously demonstrated the potential effectiveness of an innovative community health worker (CHW)-led, digitally supported follow-up model for improving childhood immunization coverage; this model has now been adapted to address HPV vaccination among adolescent girls in the same communities.

To evaluate the effectiveness of a community-based CHW follow-up intervention, supported by a digital tool, in increasing HPV vaccination coverage and reducing time-to-vaccination among adolescent girls in Mali and Côte d'Ivoire, using a randomized controlled trial (RCT) design with a waitlist.

This is a multi-site, pragmatic, parallel-group RCT with a waitlist (delayed-intervention) design, implemented across Muso Health catchment areas in Mali and Côte d'Ivoire. Eligible participants are adolescent girls who are, or will become, eligible for HPV vaccination during the study period (aged 10 years in Mali; 9-14 years in Côte d'Ivoire). Eligible girls are randomized 1:1, stratified by country, site, and CHW supervision zone, to: (i) a control arm receiving standard community mobilization; or (ii) an intervention arm receiving proactive CHW home visits guided by a digital tool with real-time data visualization and automated task reminders. After the phase 1 assessment (3 months post-launch), the control arm crosses over to receive the intervention (waitlist activation), followed by a phase 2 assessment at 6 months. The primary outcome is HPV vaccination coverage (proportion vaccinated among eligible girls) compared between arms at the phase 1 endline. The secondary outcome is the time (in days) from study initiation to vaccination. The planned total sample size is 17,188 adolescent girls (9,550 intervention; 7,638 control), providing 80% power at α = 0.05 to detect a minimum absolute difference of 0.94 percentage points (19% relative increase) over an estimated baseline coverage of 4.95%. Primary analyses will use mixed-effects logistic regression (coverage) and Cox proportional hazards (time-to-vaccination), both clustered at the CHW supervision zone level, as detailed in the study's pre-registered Statistical Analysis Plan.

Verbal informed consent was obtained from participants (or their parents/guardians, given participants' minor status) prior to vaccination status assessment, in view of low literacy rates in the study population. The protocol has been submitted to the relevant national and institutional ethical review boards in Mali and Côte d'Ivoire for approval or exemption. Findings will be disseminated through peer-reviewed publication, stakeholder workshops, and policy briefs to inform HPV immunization strategies in comparable low-resource settings.