Health and economic impacts of Lassa vaccination campaigns in West Africa

David R M Smith; Joanne Turner; Patrick Fahr; Lauren A Attfield; Paul R Bessell; Christl A Donnelly; Rory Gibb; Kate E Jones; David W Redding; Danny Asogun; Oladele Oluwafemi Ayodeji; Benedict N Azuogu; William A Fischer 2nd; Kamji Jan; Adebola T Olayinka; David A Wohl; Andrew A Torkelson; Katelyn A Dinkel; Emily J Nixon; Koen B Pouwels; T Déirdre Hollingsworth

doi:10.1038/s41591-024-03232-y

Health and economic impacts of Lassa vaccination campaigns in West Africa

Nat Med. 2024 Aug 28. doi: 10.1038/s41591-024-03232-y. Online ahead of print.

Authors

David R M Smith^#¹, Joanne Turner^#^{2

3}, Patrick Fahr⁴, Lauren A Attfield^{5

6}, Paul R Bessell⁷, Christl A Donnelly^{6

8

9}, Rory Gibb⁵, Kate E Jones⁵, David W Redding¹⁰, Danny Asogun¹¹, Oladele Oluwafemi Ayodeji¹², Benedict N Azuogu¹³, William A Fischer 2nd¹⁴, Kamji Jan¹⁵, Adebola T Olayinka¹⁵, David A Wohl¹⁴, Andrew A Torkelson¹⁶, Katelyn A Dinkel¹⁶, Emily J Nixon², Koen B Pouwels¹⁷, T Déirdre Hollingsworth^{18

19}

Affiliations

¹ Nuffield Department of Population Health, Health Economics Research Centre, University of Oxford, Oxford, UK. david.smith@ndph.ox.ac.uk.
² Department of Mathematical Sciences, University of Liverpool, Liverpool, UK.
³ Department of Livestock and One Health, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK.
⁴ Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.
⁵ Department of Genetics, Evolution and Environment, Centre for Biodiversity and Environment Research, University College London, London, UK.
⁶ Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
⁷ Independent consultant, Edinburgh, UK.
⁸ Department of Statistics, University of Oxford, Oxford, UK.
⁹ Pandemic Sciences Institute, University of Oxford, Oxford, UK.
¹⁰ Science Department, The Natural History Museum, London, UK.
¹¹ Irrua Specialist Teaching Hospital, Irrua, Nigeria.
¹² Federal Medical Centre, Owo, Nigeria.
¹³ Alex Ekwueme Federal University Teaching Hospital Abakaliki, Abakaliki, Nigeria.
¹⁴ Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA.
¹⁵ Nigeria Centre for Disease Control and Prevention, Abuja, Nigeria.
¹⁶ Linksbridge SPC, Seattle, WA, USA.
¹⁷ Nuffield Department of Population Health, Health Economics Research Centre, University of Oxford, Oxford, UK.
¹⁸ Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK.
¹⁹ Nuffield Department of Medicine, NDM Centre for Global Health Research, University of Oxford, Oxford, UK.

^# Contributed equally.

PMID: 39198710
DOI: 10.1038/s41591-024-03232-y

Abstract

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.