Objective To estimate population health outcomes with delayed second dose versus standard schedule of SARS-CoV-2 mRNA vaccination. Design Simulation agent based modeling study. Setting Simulated population based on real world US county. Participants The simulation included 100 000 agents, with a representative distribution of demographics and occupations. Networks of contacts were established to simulate potentially infectious interactions though occupation, household, and random interactions. Interventions Simulation of standard covid-19 vaccination versus delayed second dose vaccination prioritizing the first dose. The simulation runs were replicated 10 times. Sensitivity analyses included first dose vaccine efficacy of 50%, 60%, 70%, 80%, and 90% after day 12 post-vaccination; vaccination rate of 0.1%, 0.3%, and 1% of population per day; assuming the vaccine prevents only symptoms but not asymptomatic spread (that is, non-sterilizing vaccine); and an alternative vaccination strategy that implements delayed second dose for people under 65 years of age, but not until all those above this age have been vaccinated. Main outcome measures Cumulative covid-19 mortality, cumulative SARS-CoV-2 infections, and cumulative hospital admissions due to covid-19 over 180 days. Results Over all simulation replications, the median cumulative mortality per 100 000 for standard dosing versus delayed second dose was 226 v 179, 233 v 207, and 235 v 236 for 90%, 80%, and 70% first dose efficacy, respectively. The delayed second dose strategy was optimal for vaccine efficacies at or above 80% and vaccination rates at or below 0.3% of the population per day, under both sterilizing and non-sterilizing vaccine assumptions, resulting in absolute cumulative mortality reductions between 26 and 47 per 100 000. The delayed second dose strategy for people under 65 performed consistently well under all vaccination rates tested. Conclusions A delayed second dose vaccination strategy, at least for people aged under 65, could result in reduced cumulative mortality under certain conditions.

中文翻译：

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延迟第二剂BNT162b2或mRNA-1273 covid-19疫苗的公共卫生影响：基于模拟剂的建模研究

目的评估延迟第二剂量与SARS-CoV-2 mRNA疫苗接种的标准时间表后的人群健康状况。基于Design Simulation Agent的建模研究。根据现实世界的美国县设置模拟人口。参与者模拟包括100 000名特工，具有人口统计学和职业的代表性分布。建立了联系网络以模拟通过职业，家庭和随机互动而可能引起的传染性互动。干预模拟标准covid-19疫苗接种与优先第二剂疫苗的第二剂疫苗的延迟接种。模拟运行重复10次。敏感性分析包括接种后第12天的第一剂疫苗效力分别为50％，60％，70％，80％和90％；每天的疫苗接种率分别为人口的0.1％，0.3％和1％；假设疫苗只能预防症状而不能无症状扩散（即非灭菌疫苗）；以及另一种疫苗接种策略，该策略可对65岁以下的人群实施第二次延迟接种，但要等到所有高于该年龄的人群都进行疫苗接种。主要结局指标是180天内累积的covid-19死亡率，累计SARS-CoV-2感染以及因covid-19导致的累计住院人数。结果在所有模拟重复中，标准剂量与延迟第二剂量的每10万中位累积死亡率分别为90％，80％和70％第一剂量功效分别为226 v 179、233 v 207和235 v 236。对于每天疫苗接种率等于或高于80％，疫苗接种率等于或低于人群的0.3％，延迟第二剂策略是最佳选择，在灭菌和非灭菌疫苗的假设下，绝对累积死亡率降低了每10万26至47之间。65岁以下人群的延迟第二剂策略在所有测试的疫苗接种率下均表现良好。结论至少对于65岁以下的人群，延迟的第二剂疫苗接种策略可能会导致在某些情况下降低累积死亡率。