Imperial students build $5 tracker to spot freeze-damaged vaccines

Four first-year students at Imperial College London have built an electricity-free device costing about $5 that records how often a vaccine shipment is exposed to freezing, since frozen vaccines can look normal but lose effectiveness. Their team, Kalyb, won the university's Make-A-Difference! innovation contest and a £7,000 prize, and plans to test the device in Nigeria next April.