Smith, David RM 
ORCID: 0000-0002-7330-4262, Turner, Joanne ORCID: 0000-0002-0258-2353, Fahr, Patrick ORCID: 0000-0003-2190-1513, Attfield, Lauren A ORCID: 0000-0003-3864-4111, Bessell, Paul R, Donnelly, Christl A ORCID: 0000-0002-0195-2463, Gibb, Rory ORCID: 0000-0002-0965-1649, Jones, Kate E ORCID: 0000-0001-5231-3293, Redding, David W, Asogun, Danny ORCID: 0000-0001-6811-9268 et al (show 11 more authors)
(2024)
Projecting health and economic impacts of Lassa vaccination campaigns in West Africa.
[Preprint]
Abstract
<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>Lassa fever is a zoonotic disease identified by the World Health Organization (WHO) as having pandemic potential. Estimates of the health-economic impacts of vaccination are needed to guide vaccine investments.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>We estimated rates of Lassa virus (LASV) infection across West Africa, quantified the health-economic burden of disease and evaluated impacts of a series of vaccination campaigns. We also modelled the emergence of “Lassa-X” – a hypothetical pandemic LASV variant – and evaluated impacts of the 100 Days Mission, a pandemic response initiative aimed at delivering vaccines within 100 days of such a pathogen emerging.</jats:p></jats:sec><jats:sec><jats:title>Findings</jats:title><jats:p>We estimated 2.7M (95% uncertainty interval: 2.1M-3.4M) LASV infections, 23.7K (14.9K-34.6K) hospitalisations and 3.9K (1.3K-8.3K) deaths annually, resulting over ten years in 2.0M (793.8K-3.9M) disability-adjusted life-years (DALYs) and $1.6B ($805.1M-$2.8B) in societal costs (International dollars 2021). Reaching 80% vaccine coverage in WHO-classified “endemic districts” and 5% coverage elsewhere with a vaccine 70% effective against disease prevented 3.3K (1.1K-7.0K) deaths, 164.1K (66.7K-317.7K) undiscounted DALYs and $128.2M ($67.2M-$231.9M) in discounted societal costs over ten years, thus averting approximately 11%-28% of DALYs in endemic countries. In the event of Lassa-X emerging, achieving 100 Days Mission vaccination targets averted approximately 22% of DALYs given a vaccine 70% effective against disease and 74% of DALYs given a vaccine 70% effective against both infection and disease.</jats:p></jats:sec><jats:sec><jats:title>Interpretation</jats:title><jats:p>Vaccination will help alleviate Lassa fever’s health-economic burden. Investing in Lassa vaccination now may help prepare against potential future variants with pandemic potential.</jats:p></jats:sec><jats:sec><jats:title>Funding</jats:title><jats:p>Coalition for Epidemic Preparedness Innovations.</jats:p></jats:sec><jats:sec><jats:title>Evidence before this study</jats:title><jats:p>Lassa fever is a common but widely underreported emerging zoonotic disease endemic to West Africa. At least four Lassa vaccine candidates have begun clinical trials. We searched PubMed and preprint archives MedRxiv and BioRxiv up to 26 February 2024 for journal articles using the query (LASV OR Lassa) AND vaccin* AND (burden OR health-econ* OR econ* OR projection) without data or language restrictions. Several articles addressed Lassa vaccine candidates currently in development, including laboratory studies, experiments in animal models and one first-in-human phase 1 clinical trial. Reviews and editorials have discussed extensive gaps in Lassa fever surveillance, recent efforts to scale-up vaccine investment and challenges in designing efficient vaccination campaigns. However, no studies have attempted to estimate the potential impacts of Lassa vaccination on population health or economies. Estimates of Lassa fever burden and vaccine impact are needed to guide epidemiological study design and investment in Lassa vaccine development.</jats:p></jats:sec><jats:sec><jats:title>Added value of this study</jats:title><jats:p>We provide the first estimates of the health-economic burden of Lassa fever, synthesizing recent data on zoonotic risk, human-to-human transmission, clinical outcomes and economic costs associated with infection. We assess a series of vaccination campaigns and describe their projected impacts on population health and economies across the 15 countries of continental West Africa. We also consider a scenario describing the emergence of Lassa-X, a hypothetical novel Lassa-related virus with pandemic potential. We quantify health-economic impacts of reactive Lassa-X vaccination campaigns in line with the stated goals of the 100 Days Mission.</jats:p></jats:sec><jats:sec><jats:title>Implications of all the available evidence</jats:title><jats:p>Our analysis predicts that vaccination campaigns predominantly targeting districts of Guinea, Liberia, Sierra Leone and Nigeria currently classified as endemic by WHO could substantially reduce the health-economic burden of Lassa fever. However, we further predict extensive underreported LASV infection in neighbouring regions, suggesting potential for significant benefits to expanding Lassa vaccination beyond WHO-classified endemic districts. In order to optimize vaccine rollout, improved surveillance is needed to better define populations at greatest risk of infection and severe disease throughout West Africa. Our study further demonstrates the critical health and economic benefits of achieving 100 Days Mission vaccination goals in response to a hypothetical pandemic variant of Lassa virus emerging. Although the probability of such a variant emerging is unknown, this analysis demonstrates potential for additional large-scale benefits to Lassa vaccine investment.</jats:p></jats:sec>
| Item Type: | Preprint |
|---|---|
| Uncontrolled Keywords: | Vaccine Related, Rare Diseases, Infectious Diseases, Prevention, Emerging Infectious Diseases, Immunization, 3.4 Vaccines, 3 Prevention of disease and conditions, and promotion of well-being, Infection, 3 Good Health and Well Being |
| Divisions: | Faculty of Health and Life Sciences Faculty of Science and Engineering > School of Physical Sciences Faculty of Health and Life Sciences > Institute of Infection, Veterinary and Ecological Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 29 Feb 2024 16:52 |
| Last Modified: | 27 Apr 2024 23:14 |
| DOI: | 10.1101/2024.02.26.24303394 |
| Open Access URL: | https://www.medrxiv.org/content/10.1101/2024.02.26... |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3179018 |
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