Department of Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
Research Center for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran.
J Res Health Sci. 2021 Apr 25;21(2):e00514. doi: 10.34172/jrhs.2021.48.
This study aimed to determine the secondary attack rate (SAR) and its determinants to describe the clinical features and epidemiological aspects of patients and determine the risk factors of COVID-19 among household contacts in Hamadan Province, west of Iran.
A cohort study.
In this cohort study, a total of 323 index cases and 989 related close contacts ages more than 15 years old (family members, relatives, and co-workers) were enrolled using a manual contact tracing approach, and all participants were tested by reverse transcription polymerase chain reaction test. In this research, the frequency of symptoms was assessed, the SAR among contacts of index cases was calculated, and the risk factors of COVID-19 were evaluated by the logistic regression model.
The secondary attack rate for total household members of index cases was estimated at 31.7% (95% CI: 28.8-34.7). It was found that among household contacts, the highest SARs were related to spouses 47.1% (95% CI: 38.7-55.7) and grandparents/parents 39.3% (95% CI: 29.4, 49.9) of index cases, who had also higher risks to become secondary cases (adjusted odds ratio [OR]=2.98, 95% CI: 1.31-6.75 and adjusted OR=2.76, 95% CI: 1.18-6.44, respectively). Considering the occupation of contacts, unemployed and retired people and housewives were most susceptible for transmission of COVID-19. It was revealed that cough was the most prevalent symptom among index and secondary cases.
Our findings indicated that spouses and grandparents/parents of index cases were the most susceptible individuals for COVID-19 transmission. Prolonged exposure with index case before COVID-19 diagnosis raised the chance of infection among secondary cases.
本研究旨在确定继发感染率（SAR）及其决定因素，以描述患者的临床特征和流行病学特征，并确定伊朗西部哈马丹省 COVID-19 家庭接触者中的危险因素。
队列研究。
在这项队列研究中，通过手动接触追踪方法共招募了 323 名索引病例和 989 名相关密切接触者（年龄在 15 岁以上的家庭成员、亲属和同事），所有参与者均接受了逆转录聚合酶链反应检测。在这项研究中，评估了症状的频率，计算了索引病例接触者中的 SAR，并通过逻辑回归模型评估了 COVID-19 的危险因素。
估计索引病例的所有家庭成员的继发感染率为 31.7%（95%CI：28.8-34.7）。结果发现，在家庭接触者中，SAR 最高的是配偶（47.1%，95%CI：38.7-55.7）和祖父母/父母（39.3%，95%CI：29.4，49.9），他们成为继发病例的风险也更高（调整后的优势比[OR]=2.98，95%CI：1.31-6.75 和调整后的 OR=2.76，95%CI：1.18-6.44）。考虑到接触者的职业，失业和退休人员以及家庭主妇最容易传播 COVID-19。结果表明，咳嗽是索引和继发病例中最常见的症状。
我们的研究结果表明，索引病例的配偶和祖父母/父母是 COVID-19 传播的最易感个体。在 COVID-19 诊断前与索引病例的长时间接触增加了继发病例感染的机会。
