Yamamura Osamu, Onishi Hidenori, Sakamaki Ippei, Fujita Ryousuke, Miyashita Hirofumi, Iwasaki Hiromichi
Department of Community Medicine, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan.
Department of Infectious Diseases, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan.
Asian Biomed (Res Rev News). 2023 Oct 9;17(3):115-123. doi: 10.2478/abm-2023-0051. eCollection 2023 Jun.
In Japan, on April 20, 2020, the definition of a close contact regarding coronavirus disease (COVID-19) was changed from a long-term contact time to a specified contact time of 15 min and from a contact distance of 2 m to 1 m.
We aimed to determine the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection rate among close contacts of patients with COVID-19 and determine the impact of the infection on transmission among close contacts.
The numbers of SARS-CoV-2 tests, SARS-CoV-2-positive cases, and close contacts of patients with COVID-19 were assessed between March 2020 and February 2021 in Fukui Prefecture, Japan. The study period was subdivided into 3 periods. The second and third period contained data with the changed definition of close contact.
Overall, 32,238 SARS-CoV-2 tests were performed. There were 545 patients with COVID-19 and 1487 close contacts, of whom 267 tested positive. The highest infection rate occurred in period 3. Distance, protective measures, and contact time with COVID-19 patients influenced the increased infection rate. The infection rate showed a rising trend from 11.1% in period 1 to 19.2% and 20.0% in periods 2 and 3, respectively (Cochran-Armitage test; < 0.004). Multivariate analysis revealed that female sex was an independent risk factor for infection of close contacts (odds ratio: 2.23; 95% confidence interval: 1.700-2.930).
Female sex is a risk factor for transmission by close contacts. The rate of infection among close contacts may be associated with contact time, contact distance, and protective measures.
2020年4月20日，日本将冠状病毒病（COVID-19）密切接触者的定义从长时间接触改为特定接触时间15分钟，接触距离从2米改为1米。
我们旨在确定COVID-19患者密切接触者中严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的感染率，并确定感染对密切接触者之间传播的影响。
2020年3月至2021年2月期间，在日本福井县评估了SARS-CoV-2检测数量、SARS-CoV-2阳性病例以及COVID-19患者的密切接触者数量。研究期分为3个阶段。第二和第三阶段包含密切接触定义改变后的数据。
总体而言，共进行了32238次SARS-CoV-2检测。有545例COVID-19患者和1487名密切接触者，其中267人检测呈阳性。感染率最高的是第3阶段。与COVID-患者的接触距离、防护措施和接触时间影响了感染率的上升。感染率呈上升趋势，第1阶段为11.1%，第2阶段和第3阶段分别为19.2%和20.0%（ Cochr an-Armitage检验；<0.004）。多变量分析显示，女性是密切接触者感染的独立危险因素（优势比：2.23；95%置信区间：1.700-2.930）。
女性是密切接触传播的危险因素。密切接触者中的感染率可能与接触时间、接触距离和防护措施有关。
