Department of Pediatrics, Phuentsholing Hospital, Chukha, Bhutan.
Policy and Planning Division, Ministry of Health, Bhutan.
Biomed Res Int. 2022 Jul 8;2022:5644454. doi: 10.1155/2022/5644454. eCollection 2022.
The transmission trend of SARS-CoV-2 is continuously evolving. Understanding the dynamics in different settings is crucial for any effective containment measures. We aimed to study the characteristics of household transmission of SARS-CoV-2 in Bhutanese households by determining the transmissibility within household contacts of confirmed COVID-19 index cases and their factors of infectivity.
We conducted a retrospective observational study on household transmission in 306 household contacts of 93 COVID-19 positive index cases diagnosed from April 16, 2021, to June 30, 2021. A pro forma was used to collect data on the epidemiological, demographic, and clinical profile of all recruited individuals. Secondary attack rates (SAR) were calculated, and risk factors for transmission were estimated.
180 of 306 household contacts developed secondary household transmission (SAR 58.8%; 95% CI: 53.2-64.2). The median age of household contacts was 22 years. The median household size was 4 (mean 4.3 ± 2.199) members. Contacts exposed to adult index cases (aPR 1; 95% CI 1, 1.02, = 0.01) and vaccinated index cases (uPR 0.41, 95% CI 0.25, 0.66, < 0.001) had a higher SAR and prevalence of secondary infections.
Our findings suggest substantial evidence of secondary infections among household contacts, especially in the context of public health mandated lockdowns. Aggressive early contact tracing and case identification with subsequent case isolation from other household members remains a crucial step in preventing secondary transmission.
SARS-CoV-2 的传播趋势在不断演变。了解不同环境中的动态变化对于任何有效的遏制措施都至关重要。我们旨在通过确定确诊 COVID-19 索引病例的家庭接触者中的传染性，来研究不丹家庭中 SARS-CoV-2 的家庭传播特征及其感染因素。
我们对 2021 年 4 月 16 日至 2021 年 6 月 30 日期间诊断的 93 例 COVID-19 阳性索引病例的 306 名家庭接触者的家庭传播进行了回顾性观察研究。使用表格收集所有招募人员的流行病学、人口统计学和临床特征数据。计算二级攻击率（SAR），并估计传播的危险因素。
306 名家庭接触者中有 180 名（SAR 58.8%；95%CI：53.2-64.2）发生了继发性家庭传播。家庭接触者的中位年龄为 22 岁。家庭规模中位数为 4 人（平均 4.3±2.199 人）。接触成年索引病例的接触者（aPR 1；95%CI 1,1.02, = 0.01）和接种疫苗的索引病例（uPR 0.41,95%CI 0.25,0.66, < 0.001）的 SAR 和继发性感染发生率更高。
我们的研究结果表明，家庭接触者中存在大量继发性感染的证据，尤其是在公共卫生强制封锁的情况下。积极的早期接触追踪和病例识别，随后对其他家庭成员进行病例隔离，仍然是预防继发性传播的关键步骤。
