Health-economic Impacts of Age- and Sex-Targeted Lassa Fever Vaccination in Endemic West Africa

A new peer-reviwed study from Oxford University uses mathematical modelling to project the health and economic impacts of potential vaccination strategies against Lassa fever across endemic regions of Nigeria, Guinea, Liberia, and Sierra Leone from 2025 to 2037. It compares cost-effectiveness and disease outcomes of age- and sex-targeted vaccination campaigns, accounting for hospitalisations, mortality, disability-adjusted life-years (DALYs), health-care costs, and productivity losses. The model utilises Lassa mammarenavirus risk maps and epidemiological data to simulate different risk-group targeting approaches and estimate threshold vaccine costs (TVCs) — the maximum vaccine price per dose at which vaccination remains cost-effective.

Key findings

• Lassa fever contributes substantially to health burden in endemic regions, with about 6·23 hospitalisations, 0·75 deaths, and 31·1 DALYs per 100,000 person-years without vaccination.

• Targeted vaccination strategies yielded differential impacts:

  • Adolescents and adults (15–49 years) prevented the most hospitalisations and DALYs per 100,000 doses.

  • Older adults (≥50 years) had relatively high DALY reductions at certain vaccine cost points.

  • Women of childbearing age (15–49 years) resulted in notable mortality and DALY gains per dose.

• Under base assumptions, untargeted vaccination at INT$2 per dose and targeting adolescents–adults at INT$5 per dose were the most cost-effective strategies.

• At vaccine prices of INT$10 per dose or higher, none of the examined strategies remained cost-effective.

• Threshold vaccine costs (TVCs) varied by target group, with the highest for adolescents–adults (INT$7·39) and lowest for children (INT$1·94).

Thumbnail image credit: The Lancet Global Health