Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
School of Interdisciplinary Arts and Sciences, University of Washington, Tacoma, Washington, United States of America.
PLoS Negl Trop Dis. 2022 Apr 20;16(4):e0010358. doi: 10.1371/journal.pntd.0010358. eCollection 2022 Apr.
A global stockpile of oral cholera vaccine (OCV) was established in 2013 for use in outbreak response and are licensed as two-dose regimens. Vaccine availability, however, remains limited. Previous studies have found that a single dose of OCV may provide substantial protection against cholera.
Using a mathematical model with two age groups paired with optimization algorithms, we determine the optimal vaccination strategy with one and two doses of vaccine to minimize cumulative overall infections, symptomatic infections, and deaths. We explore counterfactual vaccination scenarios in three distinct settings: Maela, the largest refugee camp in Thailand, with high in- and out-migration; N'Djamena, Chad, a densely populated region; and Haiti, where departments are connected by rivers and roads.
Over the short term under limited vaccine supply, the optimal strategies for all objectives prioritize one dose to the older age group (over five years old), irrespective of setting and level of vaccination coverage. As more vaccine becomes available, it is optimal to administer a second dose for long-term protection. With enough vaccine to cover the whole population with one dose, the optimal strategies can avert up to 30% to 90% of deaths and 36% to 92% of symptomatic infections across the three settings over one year. The one-dose optimal strategies can avert 1.2 to 1.8 times as many cases and deaths compared to the standard two-dose strategy.
In an outbreak setting, speedy vaccination campaigns with a single dose of OCV is likely to avert more cases and deaths than a two-dose pro-rata campaign under a limited vaccine supply.
2013 年建立了全球口服霍乱疫苗（OCV）储备库，用于应对疫情爆发，并获得了两剂方案的许可。然而，疫苗的供应仍然有限。先前的研究发现，一剂 OCV 可能对霍乱提供实质性保护。
我们使用具有两个年龄组的数学模型和优化算法，确定使用一剂和两剂疫苗的最佳接种策略，以最大限度地减少累计总感染、有症状感染和死亡人数。我们在三个不同环境中探索了假设性的接种情景：泰国最大的难民营迈拉（Maela），移民输入和输出都很高；乍得的恩贾梅纳（N'Djamena），人口密集地区；以及海地，那里的行政区由河流和道路相连。
在短期内疫苗供应有限的情况下，所有目标的最佳策略都是优先为年龄较大的群体（五岁以上）接种一剂疫苗，无论环境和接种覆盖率如何。随着疫苗供应的增加，长期保护的最佳策略是接种第二剂。如果有足够的疫苗为所有人接种一剂，最佳策略可以在一年内避免三个环境中高达 30%至 90%的死亡和 36%至 92%的有症状感染。一剂最佳策略可以避免 1.2 到 1.8 倍的病例和死亡，而标准的两剂按比例分配策略。
在疫情爆发的情况下，与在有限的疫苗供应下进行两剂按比例分配的疫苗接种运动相比，快速的单剂 OCV 疫苗接种运动可能会避免更多的病例和死亡。
