1Jigme Dorji Wangchuck National Referral Hospital, Thimphu, Bhutan.
2Ministry of Health, Thimphu, Bhutan.
Am J Trop Med Hyg. 2020 Dec 10;104(2):490-495. doi: 10.4269/ajtmh.20-0672.
As the COVID-19 pandemic continues, there is growing concordance and persisting conflicts on the virus and the disease process. We discuss limited transmissibility of the virus by asymptomatic and mild cases of COVID-19 patients in Bhutan. We followed up the secondary transmission of SARS-CoV-2 in the contacts of asymptomatic and mild COVID-19 patients in Bhutan. Bhutan had 33 confirmed COVID-19 cases in the country as of May 29, 2020. Of these, 22 (67%) were females. Except the first two cases (American tourists), the rest were Bhutanese living outside the country. The mean age of the Bhutanese patients was 26.3 (range 16-33) years. Close contacts of 27 of the 33 cases were followed up for signs and symptoms and COVID-19 positivity. The first two cases had 73 and 97 primary contacts, respectively, and equal number of secondary contacts (224). From the third case, a mandatory 21-day facility quarantine was instituted, all primary contacts were facility quarantined, and there were no secondary contacts. In total, the 27 cases had 1,095 primary contacts and 448 secondary contacts. Of these, 75 individuals were categorized as definite high-risk contacts. Secondary transmission occurred in seven high-risk contacts. Therefore, the overall secondary transmission was 9.0% (7/75) and 0.6% (7/1,095) among the high-risk and primary contacts, respectively. No transmission occurred in the secondary contacts. In contrast to several reports indicating high transmissibility of SARS-CoV-2 in contacts of confirmed cases, the mostly young, asymptomatic, and mild cases of COVID-19 in Bhutan showed limited secondary transmission.
随着 COVID-19 大流行的持续，人们对该病毒及其疾病过程的认识不断加深，但仍存在一些争议。我们讨论了不丹 COVID-19 轻症和无症状患者病毒传播能力有限的问题。我们对不丹 COVID-19 轻症和无症状患者接触者中 SARS-CoV-2 的二次传播情况进行了随访。截至 2020 年 5 月 29 日，不丹全国共报告 33 例确诊 COVID-19 病例。其中 22 例（67%）为女性。除前两例外（两名美国游客），其余病例均为居住在国外的不丹人。不丹患者的平均年龄为 26.3 岁（16-33 岁）。对 33 例病例的 27 名密切接触者进行了症状和 COVID-19 阳性检测随访。前两例病例的一级接触者分别为 73 人和 97 人，二级接触者人数相同（224 人）。从第三例病例开始，对所有一级接触者进行了为期 21 天的设施隔离，没有二级接触者。总共，这 27 例病例有 1095 名一级接触者和 448 名二级接触者。其中 75 人被归类为明确的高风险接触者。有 7 名高风险接触者发生了二次传播。因此，高风险接触者和一级接触者的二次传播率分别为 9.0%（7/75）和 0.6%（7/1095）。二级接触者未发生传播。与几例报告称 SARS-CoV-2 在确诊病例接触者中具有高传播能力形成鲜明对比的是，不丹 COVID-19 轻症和无症状患者以年轻人为主，其二次传播能力有限。
