Romero-Brufau Santiago, Chopra Ayush, Ryu Alex J, Gel Esma, Raskar Ramesh, Kremers Walter, Anderson Karen S, Subramanian Jayakumar, Krishnamurthy Balaji, Singh Abhishek, Pasupathy Kalyan, Dong Yue, O'Horo John C, Wilson Walter R, Mitchell Oscar, Kingsley Thomas C
Department of Medicine, Mayo Clinic, Rochester, MN, USA.
Department of Biostatistics, Harvard T H Chan School of Public Health, Boston, MA, USA.
BMJ. 2021 May 12;373:n1087. doi: 10.1136/bmj.n1087.
To estimate population health outcomes with delayed second dose versus standard schedule of SARS-CoV-2 mRNA vaccination.
Simulation agent based modeling study.
Simulated population based on real world US county.
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.
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.
Cumulative covid-19 mortality, cumulative SARS-CoV-2 infections, and cumulative hospital admissions due to covid-19 over 180 days.
Over all simulation replications, the median cumulative mortality per 100 000 for standard dosing versus delayed second dose was 226 179, 233 207, and 235 236 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.
A delayed second dose vaccination strategy, at least for people aged under 65, could result in reduced cumulative mortality under certain conditions.
评估严重急性呼吸综合征冠状病毒2（SARS-CoV-2）信使核糖核酸（mRNA）疫苗延迟第二剂接种与标准接种程序相比对人群健康结局的影响。
基于模拟主体的建模研究。
基于美国真实郡县模拟人群。
模拟包括100000个主体，具有人口统计学和职业的代表性分布。通过职业、家庭和随机互动建立接触网络，以模拟潜在的感染性互动。
模拟标准新冠疫苗接种与优先接种第一剂的延迟第二剂接种。模拟运行重复10次。敏感性分析包括接种后第12天及以后第一剂疫苗效力分别为50%、60%、70%、80%和90%；每天接种率为人口的0.1%、0.3%和1%；假设疫苗仅预防症状但不预防无症状传播（即非灭菌疫苗）；以及一种替代接种策略，即对65岁以下人群实施延迟第二剂接种，但直到所有65岁及以上人群接种后才进行。
180天内的新冠累计死亡率、SARS-CoV-2累计感染数以及因新冠导致的累计住院人数。
在所有模拟重复中，对于90%、80%和70%的第一剂效力，标准剂量接种与延迟第二剂接种相比，每100000人的累计死亡率中位数分别为226对179、233对207和235对236。在灭菌和非灭菌疫苗假设下，对于效力为80%及以上且每天接种率为人口的0.3%及以下的情况，延迟第二剂接种策略是最优的，每100000人的绝对累计死亡率降低26至47。在所有测试的接种率下，针对65岁以下人群的延迟第二剂接种策略表现始终良好。
至少对于65岁以下人群，延迟第二剂接种策略在某些条件下可降低累计死亡率。
