Department of Virology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-Machi, Aoba-Ku, Sendai, Miyagi, 980-8575, Japan.
Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Sci Rep. 2023 Aug 14;13(1):13230. doi: 10.1038/s41598-023-38007-x.
Japan has implemented a cluster-based approach for coronavirus disease 2019 (COVID-19) from the pandemic's beginning based on the transmission heterogeneity (overdispersion) of severe acute respiratory coronavirus 2 (SARS-CoV-2). However, studies analyzing overdispersion of transmission among new variants of concerns (VOCs), especially for Omicron, were limited. Thus, we aimed to clarify how the transmission heterogeneity has changed with the emergence of VOCs (Alpha, Delta, and Omicron) using detailed contact tracing data in Yamagata Prefecture, Japan. We estimated the time-varying dispersion parameter ([Formula: see text]) by fitting a negative binomial distribution for each transmission generation. Our results showed that even after the emergence of VOCs, there was transmission heterogeneity of SARS-CoV-2, with changes in [Formula: see text] during each wave. Continuous monitoring of transmission dynamics is vital for implementing appropriate measures. However, a feasible and sustainable epidemiological analysis system should be established to make this possible.
日本从新冠疫情大流行开始就基于严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）的传播异质性（过离散），实施了以聚集为基础的 2019 年冠状病毒病（COVID-19）防控方法。然而，分析新出现的关注变异株（VOC），特别是奥密克戎变异株的传播过离散性的研究有限。因此，我们旨在利用日本山形县详细的接触者追踪数据，阐明随着 VOC（阿尔法、德尔塔和奥密克戎）的出现，传播异质性如何发生变化。我们通过对每一代传播进行负二项式分布拟合，估计时变离散参数([Formula: see text])。结果表明，即使出现 VOC 后，SARS-CoV-2 仍存在传播异质性，在每一波疫情中[Formula: see text]均发生变化。持续监测传播动态对于实施适当的措施至关重要。然而，应建立可行且可持续的流行病学分析系统来实现这一目标。
