Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA; Public Health Modeling Unit, Yale School of Public Health, New Haven, CT, USA.
Medical Microbiology & Infectious Diseases, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB, Canada.
Lancet Glob Health. 2024 Dec;12(12):e1936-e1944. doi: 10.1016/S2214-109X(24)00384-X. Epub 2024 Oct 9.
Mpox was first identified in the Democratic Republic of the Congo (DRC) in 1970. In 2023, a historic outbreak of mpox occurred in the country, continuing into 2024. Over 14 000 cases and 600 deaths were reported in 2023 alone, representing a major increase from previous outbreaks. The modified vaccinia Ankara vaccine (brand names JYNNEOS, Imvamune, and Imvanex) was used in the 2022 mpox outbreak in the USA and Europe. However, at the time of the study, vaccination had not been made available in the DRC. We aimed to inform policy and decision makers on the potential benefits of, and resources needed, for mpox vaccination campaigns in the DRC by providing counterfactual scenarios evaluating the short-term effects of various vaccination strategies on mpox cases and deaths, if such a vaccination campaign had been undertaken before the 2023-24 outbreak.
A dynamic transmission model was used to simulate mpox transmission in the DRC, stratified by age (<5, 5-15, and >15 years) and province. The model was used to simulate potential vaccination strategies, varying by age and region (endemic provinces, non-endemic provinces with historic cases, and all provinces) assessing the effect the strategies would have on deaths and cases in an epidemic year similar to 2023. In addition, we estimated the number of vaccine doses needed to implement each strategy.
Without vaccination, our model predicted 14 700 cases and 700 deaths from mpox over 365 days. Vaccinating 80% of all children younger than 5 years in endemic regions led to a 27% overall reduction in cases and a 43% reduction in deaths, requiring 10·5 million vaccine doses. Vaccinating 80% of all children younger than 5 years in all regions led to a 29% reduction in cases and a 43% reduction in deaths, requiring 33·1 million doses. Vaccinating 80% of children aged 15 years or younger in endemic provinces led to a 54% reduction in cases and a 71% reduction in deaths, requiring 26·6 million doses.
When resources are limited, vaccinating children aged 15 years or younger, or younger than 5 years, in endemic regions of the DRC would be the most efficient use of vaccines. Further research is needed to explore long-term effects of a one-time or recurrent vaccination campaign.
Canadian Institutes of Health Research, Canadian International Development Research Centre, US Department of Defense (Defense Threat Reduction Agency, Mpox Threat Reduction Network), Global Affairs Canada (Weapons Threat Reduction Program), US Department for Agriculture (Agriculture Research Service, Non-Assistance Cooperative Agreement).
猴痘于 1970 年在刚果民主共和国首次被发现。2023 年，该国发生了历史性的猴痘疫情，并持续到 2024 年。仅在 2023 年，就报告了超过 14000 例病例和 600 例死亡，与以往疫情相比大幅增加。改良痘苗安卡拉疫苗（商品名 JYNNEOS、Imvamune 和 Imvanex）曾用于 2022 年美国和欧洲的猴痘疫情。然而，在研究时，刚果民主共和国尚未提供疫苗接种。我们旨在通过提供假设情景，评估在 2023-24 年疫情爆发之前开展猴痘疫苗接种运动的短期效果，为决策者提供信息，说明在刚果民主共和国开展猴痘疫苗接种运动的潜在益处和所需资源。
使用动态传播模型对刚果民主共和国的猴痘传播情况进行分层，按年龄（<5 岁、5-15 岁和>15 岁）和省份进行分层。该模型用于模拟各种疫苗接种策略，如果在 2023-24 年疫情爆发之前实施这些策略，这些策略对病例和死亡的影响。此外，我们还估计了实施每种策略所需的疫苗剂量。
如果不接种疫苗，我们的模型预测 2023 年将有 14700 例猴痘病例和 700 例死亡。在流行地区为 80%的所有 5 岁以下儿童接种疫苗可使病例总数减少 27%，死亡人数减少 43%，需要 1050 万剂疫苗。在所有地区为 80%的所有 5 岁以下儿童接种疫苗可使病例总数减少 29%，死亡人数减少 43%，需要 3310 万剂疫苗。在流行地区为 80%的 15 岁或以下儿童接种疫苗可使病例总数减少 54%，死亡人数减少 71%，需要 2660 万剂疫苗。
在资源有限的情况下，在刚果民主共和国的流行地区为 80%的 15 岁或以下儿童或 5 岁以下儿童接种疫苗将是疫苗的最有效利用。需要进一步研究来探索一次性或反复疫苗接种运动的长期影响。
加拿大卫生研究院、加拿大国际发展研究中心、美国国防部（国防威胁降低局、猴痘威胁降低网络）、加拿大全球事务部（武器威胁降低计划）、美国农业部（农业研究局、非援助合作协议）。
