Background: Mass dog vaccination (MDV) prevents human rabies but remains underused in sub-Saharan Africa. The conventional annual centralised pulse campaigns require high coverage to maintain herd immunity, yet costs rise sharply as coverage increases while immunity declines rapidly between campaigns due to dog population turnover. We tested whether a community-led decentralised hybrid strategy using thermotolerant vaccines could reduce costs and sustain coverage above the 40% herd immunity threshold.
Methods: We conducted a three-year cluster-randomised trial across 112 wards in Mara Region, Tanzania (2020–2023), comparing annual pulse campaigns with a community-led hybrid strategy combining village and sub-village clinics with house-to-house vaccination. Vaccination records, costs, and household surveys from 20,335 dog-owning households were analysed using regression models. Cost-effectiveness was evaluated from provider and societal perspectives.
Results: Community-led delivery vaccinated twice as many dogs per ward annually as team-led delivery, with higher mean coverage (57% vs. 48%), and longer maintenance of the 40% herd immunity threshold (7–8 versus 5–6 months per year). Annual coverage declines by 39% without additional vaccination. Despite higher fixed costs, community-led delivery had lower marginal costs ($1.52 vs. $1.64 per dog) with a similar average cost per dog ($2.70 vs. $2.85), especially in rural settings ($2.28 vs. $2.82). The 40% coverage threshold costs $800 per ward versus $2,100 under team-led delivery, with an adjusted ICER of $2.07 per dog, suggesting low incremental cost for these gains.
Conclusions: Restructuring MDV delivery to continuous delivery directly addresses the diminishing returns and coverage declines that undermine pulse campaigns.