Health and economic impacts of Lassa vaccination campaigns in West Africa

• Published in: Nature medicine
• Main Authors: Smith, David R M, Turner, Joanne, Fahr, Patrick, Attfield, Lauren A, Bessell, Paul R, Donnelly, Christl A, Gibb, Rory, Jones, Kate E, Redding, David W, Asogun, Danny, Ayodeji, Oladele Oluwafemi, Azuogu, Benedict N, Fischer, 2nd, William A, Jan, Kamji, Olayinka, Adebola T, Wohl, David A, Torkelson, Andrew A, Dinkel, Katelyn A, Nixon, Emily J, Pouwels, Koen B, Hollingsworth, T Déirdre
• Format: Journal Article
• Language: English
• Published: United States 28.08.2024
• ISSN: 1078-8956; 1546-170X; 1546-170X
• DOI: 10.1038/s41591-024-03232-y

Lassa fever is a zoonotic disease identified by the World Health Organization (WHO) as having pandemic potential. This study estimates the health-economic burden of Lassa fever throughout West Africa and projects impacts of a series of vaccination campaigns. We also model the emergence of 'Lassa-X'-a hypothetical pandemic Lassa virus variant-and project impacts of achieving 100 Days Mission vaccination targets. Our model predicted 2.7 million (95% uncertainty interval: 2.1-3.4 million) Lassa virus infections annually, resulting over 10 years in 2.0 million (793,800-3.9 million) disability-adjusted life years (DALYs). The most effective vaccination strategy was a population-wide preventive campaign primarily targeting WHO-classified 'endemic' districts. Under conservative vaccine efficacy assumptions, this campaign averted $20.1 million ($8.2-$39.0 million) in lost DALY value and $128.2 million ($67.2-$231.9 million) in societal costs (2021 international dollars ($)). Reactive vaccination in response to local outbreaks averted just one-tenth the health-economic burden of preventive campaigns. In the event of Lassa-X emerging, spreading throughout West Africa and causing approximately 1.2 million DALYs within 2 years, 100 Days Mission vaccination averted 22% of DALYs given a vaccine 70% effective against disease and 74% of DALYs given a vaccine 70% effective against both infection and disease. These findings suggest how vaccination could alleviate Lassa fever's burden and assist in pandemic preparedness.