Cost of health systems strengthening for small and sick newborn care in four sub-Saharan African countries implemented with NEST360: incremental cost analyses

Background: Newborn survival requires high-quality small and sick newborn care (SSNC). Domestic and donor financing for SSNC is low, yet real-world cost data to inform investment are scarce. We analysed primary financial data for SSNC health system improvements nationally in Malawi and subnationally in Kenya, Nigeria, and Tanzania. Methods: We analysed incremental health system perspective costs using hospital-specific assessments, inpatient data (n=93 942 admissions per year), and government and NEST360 costs. We compared annual hospital-specific costs post-implementation (June, 2022, to June, 2023) and pre-implementation (September, 2019, to March, 2021). We calculated per-hospital and per-baby costs disaggregating by health system building blocks and payers. We benchmarked per-hospital costs for Tanzania against national SSNC investment modelled costs for high-quality care. Findings: Mean costs per referral hospital ranged from US$125 286 in Nigeria to $296 706 in Tanzania; higher costs were associated with hospitals receiving substantial health system inputs. Per-hospital costs were lower in Malawian district hospitals ($67 874) than in referral hospitals ($178 724). Mean per-baby cost ranged from $69 in Kenya to $265 in Nigeria; lower admissions were associated with higher per-baby costs in Nigeria. Mean per-baby cost in Malawian district hospitals was $132. The most substantial cost driver for governments was human resources, exceeding half of total cost in all countries except Kenya, where nurse numbers declined. Top cost drivers for NEST360 were data systems and devices. Benchmarking measured costs ($251 046 per Tanzanian hospital) with Tanzania's investment case ($669 447 per hospital) suggested that investments need to triple to reach government high-quality norms. Interpretation: Governments and partners are investing in human resources, data systems, and medical devices and supplies. More investments are required to achieve high-quality care and accelerate progress towards newborn survival targets. Funding: Gates Foundation, ELMA Philanthropies, the Mohamed bin Zayed Foundation for Humanity, the Beginnings Fund, Sall Family Foundation, private donors, and previously John D and Catherine T MacArthur Foundation.