Niels Bohr Institute, University of Copenhagen, 2100 København Ø, Denmark;
Niels Bohr Institute, University of Copenhagen, 2100 København Ø, Denmark.
Proc Natl Acad Sci U S A. 2021 Apr 6;118(14). doi: 10.1073/pnas.2016623118.
Increasing evidence indicates that superspreading plays a dominant role in COVID-19 transmission. Recent estimates suggest that the dispersion parameter for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is on the order of 0.1, which corresponds to about 10% of cases being the source of 80% of infections. To investigate how overdispersion might affect the outcome of various mitigation strategies, we developed an agent-based model with a social network that allows transmission through contact in three sectors: "close" (a small, unchanging group of mutual contacts as might be found in a household), "regular" (a larger, unchanging group as might be found in a workplace or school), and "random" (drawn from the entire model population and not repeated regularly). We assigned individual infectivity from a gamma distribution with dispersion parameter We found that when was low (i.e., greater heterogeneity, more superspreading events), reducing random sector contacts had a far greater impact on the epidemic trajectory than did reducing regular contacts; when was high (i.e., less heterogeneity, no superspreading events), that difference disappeared. These results suggest that overdispersion of COVID-19 transmission gives the virus an Achilles' heel: Reducing contacts between people who do not regularly meet would substantially reduce the pandemic, while reducing repeated contacts in defined social groups would be less effective.
越来越多的证据表明，超级传播者在 COVID-19 的传播中起着主导作用。最近的估计表明，严重急性呼吸系统综合症冠状病毒 2（SARS-CoV-2）的分散参数约为 0.1，这意味着大约 10%的病例是 80%感染的源头。为了研究过度分散如何影响各种缓解策略的结果，我们开发了一个基于代理的模型，该模型具有一个社交网络，允许通过三个部门的接触进行传播：“密切”（一小部分不变的相互接触群体，可能存在于家庭中），“常规”（更大、不变的群体，可能存在于工作场所或学校）和“随机”（从整个模型人群中抽取，不会定期重复）。我们从具有分散参数的伽马分布中分配个体传染性。我们发现，当 较低（即异质性更大，超级传播事件更多）时，减少随机部门的接触对疫情轨迹的影响远远大于减少常规接触的影响；当 较高（即异质性较小，没有超级传播事件）时，这种差异就消失了。这些结果表明，COVID-19 传播的过度分散给病毒带来了致命弱点：减少不经常见面的人之间的接触将大大减少大流行，而减少定义明确的社会团体中的重复接触效果则不那么明显。
