Social impact bonds for cancer prevention, repaid from avoided treatment costs

Outcome-based contracts in which private or philanthropic investors finance delivery programmes (HPV catch-up vaccination for adults up to 26 or 45, lung screening enrolment among smokers, hepatitis B and C test-and-treat, bowel screening uptake in low-participation areas) and the payer repays with a return only when independently verified coverage or diagnosis-stage targets are met. This shifts the risk of implementation failure from the health system to investors and aligns incentives on measured outcomes. Precedents exist in social care and in tuberculosis and HIV programmes in several countries.