Mass vaccination with two-dose Oral cholera vaccine in vulnerable populations, using existing public health infrastructure from planning to delivery through multi-sectoral collaboration in West Bengal, India

BACKGROUND: Cholera continues to pose a serious public health threat in India, particularly in flood-prone and resource-constrained settings where water, sanitation, and hygiene (WASH) infrastructure is inadequate. OCV offers an economically favorable and scalable solution in such contexts. This study evaluated the feasibility, coverage, safety, and delivery cost of a pre-emptive two-doses OCV campaign conducted through the routine public health system. METHODS: This descriptive implementation study, conducted in Bishnupur-II block of South 24 Parganas, West Bengal, enumerated 45,073 individuals across three Gram Panchayats through a household census that generated a vaccination line list with unique household identifiers. The campaign, executed in two phases (October and November 2024), utilized census-based microplanning, door-to-door vaccination by ASHAs and AWWs, and cold-chain management through the local health system. Outcomes included coverage (≥1 dose; 2-doses), AEFIs, and program costs. Costs estimated via activity-based micro-costing from the health-system perspective, excluding research costs; reported in INR with USD equivalents. RESULTS: Of the target population, first-dose coverage reached 66.4% (29,929/45,073) and two-dose coverage 63.1% (28,461/45,073), with a second-dose retention rate of 95.1% (28,461/29,929). Coverage exceeded 75% in children aged 1-5 years and varied across sub-centers (46.3%-86.2%) for both doses. Only mild adverse events were recorded [0.3% (167 cases/58,390 doses)] with no serious events. The overall expenditure was INR 12,493,303 (USD 150,521.72), with vaccine procurement accounting for 97% (INR 12,096,000; USD 145,734.94). The per-person delivery cost was INR 13.24 (USD 0.16), and the total cost, including procurement and delivery per fully vaccinated person was INR 416.44 (USD 5.01). CONCLUSIONS: The campaign demonstrates that large-scale pre-emptive OCV delivery is feasible, safe, and affordable within India's public health infrastructure. The West Bengal strategy provides a replicable framework for future cholera control efforts in similar high-risk settings across South and Southeast Asia, aligning with WHO's Ending Cholera: A Global Roadmap to 2030.