Cold-chain logistics for vaccines in Bonthe District

Vaccines bound for the Bonthe District island chiefdoms travel four-to-seven hours by boat from Bo, often arriving at temperatures outside the 2–8°C window the manufacturer requires. Nurses we interviewed estimate that one in five vials is visibly compromised on arrival and another share is silently spoiled. The current ledger is paper: when a batch goes bad, the cause is rarely traceable.

The opportunity is a small, low-power data logger paired with a lightweight handover app that captures who carried the cooler when, and at what temperature. The cost of the logger needs to come in under US$15 per unit and survive a saltwater commute.