Acceptability of an Incentivized Peer Referral Intervention to Address COVID-19 Vaccine Hesitancy Among Adults in Yopougon-Est, Côte d'Ivoire

"This intervention builds on existing evidence demonstrating the role of social networks in influencing individual behavior."

Vaccine hesitancy persists as a barrier to uptake of COVID-19 and other vaccinations across geographies, including Côte d'Ivoire. As of September 18 2022, only 33.43% of Ivorians were fully vaccinated against COVID-19. The COVID-19: Social Marketing and Behavioral Science Tools and Approaches for Optimizing Throughput at Mass Vaccination Sites in sub-Saharan Africa project was designed to increase demand for COVID-19 vaccination, especially among vaccine-hesitant adults in Yopougon-Est. The paper describes the incentivised peer referral intervention that was developed as part of this project and assesses its acceptability and effectiveness.

Starting in November 2021, FHI 360 conducted formative research with students, religious leaders, newly vaccinated individuals, and unvaccinated men and women to identify drivers of COVID-19 vaccine uptake and hesitancy. This research informed the design of demand-creation activities that were implemented through August 2023. The activities included radio spots and public service announcements, print materials (e.g., posters, flyers) and improved signage for vaccination sites, small trinkets for newly vaccinated individuals (e.g., "I am vaccinated" stickers and bracelets), and mobilisation activities, implemented by a community-based partner, such as home visits and small group discussions conducted with established women's and church groups.

Demand among adults for COVID-19 vaccinations in Yopougon-Est decreased after the government integrated the vaccines into routine immunisation services. In response, district officials requested that the project design targeted interventions to address this drop in demand. FHI 360 began by reviewing the formative research conducted earlier to identify insights that might inform these interventions. A key insight was that while family and peer support for vaccination was one of the most important factors influencing COVID-19 vaccine uptake, few vaccinated individuals routinely discussed their status or experience with others. One of the interventions they developed was the Enhanced Peer Outreach Approach, which gave monetary incentives to newly vaccinated individuals when they acted as peer mobilisers and referred family and friends for COVID-19 vaccination with paper coupons.This approach was inspired by a similar method for HIV case identification used at FHI 360: the Enhanced Peer Outreach Approach (EPOA).

From May through June 2023, the Incentivized Peer Referral intervention operated at 2 vaccination sites, where staff approached individuals immediately after receiving COVID-19 vaccination. Interested vaccine recipients received up to 9 referral coupons to distribute among their social circles, with a small financial incentive (approximately US$3) offered for each person they referred who returned to 1 of the 2 sites for COVID-19 vaccination. Intervention staff spent a few minutes with each peer mobiliser describing the coupon system, emphasising the voluntary nature of referrals, and answering questions. They did not train peer mobilisers; the intervention relied on peers sharing their personal experiences as testimony to overcome barriers rather than investing resources in training and requiring them to disseminate key messages. A community-based partner supervised intervention staff.

Of the 450 vaccinated individuals approached to be peer mobilisers, 197 opted in, distributing up to 1,041 coupons to family and peers over a 6-week period. (There was an even split in sex: 99 men and 98 women opted to distribute coupons. Age of peer mobilisers ranged from 18 to 64 years.) From those coupons, 399 individuals returned for vaccination, for a response rate of 38%. Of the 399 returned coupons, 70% were associated with networks of 10 or more individuals; 35% were associated with networks of 90 individuals, stemming from only 2 initial peer mobilisers.

FHI 360 conducted 46 key informant interviews with subsets of different groups, including 29 referred peer mobilisers (individuals who agreed to distribute coupons after being referred themselves for vaccination), 11 referred peers who declined to distribute coupons, and 6 public sector vaccination staff who participated in implementation. Select findings:

• The referred vaccine recipients reported that the intervention influenced vaccine uptake in 2 primary ways. First, many said the coupons served as prompts, both for the peer mobiliser and referred peer. Second, several referred peers reported learning about the experience of vaccinated peers and knowing that people around them were vaccinated reassured and relieved fears related to vaccination. "Incentivized peer referral interventions may encourage vaccinated individuals to discuss personal experiences to allay rumors and fears that contribute to vaccine hesitancy."
• All respondents reported that the modest compensation (approximately US$3) for peer mobilisers was socially acceptable in Yopougon-Est and sufficient to cover local transportation and phone calls related to coupon distribution and follow-up efforts. There was no evidence implying that this amount was coercive.
• Some vaccination staff said they appreciated that the intervention encouraged the public to seek services rather than obliging providers to conduct continuous outreach to promote vaccination.
• Public health officials reported that this intervention could be integrated into routine vaccination services with relatively low cost and effort.

Reflecting on the findings, FHI 360 notes that this intervention reached individuals who had not yet been vaccinated against COVID-19 more than 2 years after the vaccine's introduction in Côte d'Ivoire. Practitioners can adapt this incentivised peer referral intervention to other geographies and vaccination settings - particularly where awareness of peers' vaccination status is low, and community trust and peer influence are significant drivers of vaccine uptake - using the implementation guide, training materials, and data collection tools that were developed based on this experience pilot testing the intervention.

To that end, the paper provides insights for practitioners interested in replicating this intervention in contexts where hesitancy may affect vaccine uptake:

• Site selection plays an important role in the speed of peer mobiliser recruitment. At lower-volume sites, it might be necessary to employ complementary recruitment approaches.
• It may be important to allow the intervention to run for 7 or 8 weeks to identify enough highly productive peer mobilisers to observe exponential increases in referrals.
• This intervention employed community mobilisers supervised by a local organisation as recruiting agents. In other low-volume contexts, especially those with flexible payment structures, a service provider could play the role of the recruiting agent.
• A consultant hired by FHI 360 was responsible for oversight and verification of returned coupons and payments. This role assured accountability and smooth operation.
• Monetary incentives will not work in every context; appropriateness and potential for abuse were primary themes FHI 360 explored with acceptability questions during the pilot. They recommend this process of consultation and monitoring for other programmes considering incentivised referrals.

"Overall, this innovative strategy holds promise for improving vaccination coverage and fostering community engagement in vaccination efforts in similar contexts worldwide."