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 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
Nuffield Department of Population Health, Health Economics Research Centre, University of Oxford, Oxford, UK.
Department of Mathematical Sciences, University of Liverpool, Liverpool, UK.
Nat Med. 2024 Dec;30(12):3568-3577. doi: 10.1038/s41591-024-03232-y. Epub 2024 Aug 28.
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.
拉沙热是一种人畜共患病，世界卫生组织（WHO）认定其具有大流行潜力。本研究估算了整个西非地区拉沙热的健康经济负担，并预测了一系列疫苗接种活动的影响。我们还模拟了“拉沙-X”（一种假设的拉沙病毒大流行变体）的出现，并预测了实现“百日使命”疫苗接种目标的影响。我们的模型预测，每年有270万例（95%不确定性区间：210万-340万例）拉沙病毒感染，10年间导致200万（79.38万-390万）伤残调整生命年（DALYs）。最有效的疫苗接种策略是开展全人群预防活动，主要针对WHO分类的“地方性流行”地区。在保守的疫苗效力假设下，该活动避免了2010万美元（820万-3900万美元）的DALY价值损失以及1.282亿美元（6720万-2.319亿美元）的社会成本（2021年国际美元）。针对局部疫情的应急疫苗接种避免的健康经济负担仅为预防活动的十分之一。如果“拉沙-X”出现，在西非地区传播并在2年内造成约120万DALYs，在疫苗对疾病效力为70%的情况下，“百日使命”疫苗接种避免了22%的DALYs；在疫苗对感染和疾病效力均为70%的情况下，避免了74%的DALYs。这些研究结果表明了疫苗接种如何减轻拉沙热负担并有助于大流行防范。
