Malaria prevention in pregnancy has highly effective tools, yet the existence of a bed net does not guarantee that a pregnant woman receives, redeems and uses one. The HASA studies in Tanzania make that implementation gap unusually visible because they separate the digital intervention from the workflow around it.
In the cluster-randomized trial, all participants received an electronic voucher for a long-lasting insecticidal net. The experimental question was whether additional behaviour-change text messages would increase voucher redemption. They did not. That null result is scientifically useful because it shows that more messaging is not automatically better when both groups already receive a strong access mechanism.
The process evaluation explains why redemption still failed for some women. Nurses reported connectivity problems, increased workload and inadequate support. Participants described lost voucher numbers, retailer-system problems, stockouts, competing obligations, missing messages and insufficient explanation. The lesson is not that e-vouchers do not work. It is that an effective prevention product has to travel through staff, networks, phones, retailers, inventory, time and understanding before it reaches the person.
Publications behind this Insight
A Bed-Net Voucher Was Feasible at Scale — but Extra Text Messages Did Not Increase Redemption
A Bed-Net Voucher Was Feasible at Scale — but Extra Text Messages Did Not Increase Redemption. 2025. 10.2196/51524.
Open publicationWhy the Voucher Was Not Enough: What HASA Learned About Implementation
Why the Voucher Was Not Enough: What HASA Learned About Implementation. 2024. 10.2196/51527.
Open publicationEvidence behind this Insight
- 1. Vey T, et al. HASA cluster-randomized trial. JMIR. 2025. DOI 10.2196/51524. A Bed-Net Voucher Was Feasible at Scale — but Extra Text Messages Did Not Increase Redemption
- 2. Vey T, et al. HASA process evaluation. JMIR. 2024. DOI 10.2196/51527. Why the Voucher Was Not Enough: What HASA Learned About Implementation