National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam.
Mohawk College, Hamilton, Ontario, Canada.
Western Pac Surveill Response J. 2021 Dec 22;12(4):1-6. doi: 10.5365/wpsar.2021.12.4.833. eCollection 2021 Oct-Dec.
Viet Nam confirmed its first case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on 23 January 2020 among travellers from Wuhan, China, and experienced several clusters of community transmission until September. Viet Nam implemented an aggressive testing, isolation, contact tracing and quarantine strategy in response to all laboratory-confirmed cases. We report the results of SARS-CoV-2 testing during the first half of 2020 in northern Viet Nam.
Between January and May 2020, 15 650 upper respiratory tract specimens were collected from 14 470 suspected cases and contacts in northern Viet Nam. All were tested for SARS-CoV-2 by real-time RT-PCR. Individuals with positive specimens were tested every three days until two tests were negative. Positive specimens from 81 individuals were cultured.
Among 14 470 tested individuals, 158 (1.1%) cases of SARS-CoV-2 infection were confirmed; 89 were imported and 69 were associated with community transmission. Most patients (122, 77%) had negative results after two tests, while 11 and 4 still tested positive when sampled a third and fourth time, respectively. SARS-CoV-2 was isolated from 29 of 81 specimens (36%) with a cycle threshold (Ct) value < 30. Seven patients who tested positive again after testing negative had Ct values > 30 and negative cultures.
Early, widespread testing for SARS-CoV-2 in northern Viet Nam identified very few cases, which, when combined with other aggressive strategies, may have dramatically contained the epidemic. We observed rapid viral clearance and very few positive results after clearance. Large-scale molecular diagnostic testing is a critical part of early detection and containment of COVID-19 in Viet Nam and will remain necessary until vaccination is widely implemented.
2020 年 1 月 23 日，越南在从中国武汉入境的旅行者中确诊首例严重急性呼吸综合征冠状病毒 2 型（SARS-CoV-2）感染病例，并于 9 月前经历了几波社区传播。越南针对所有实验室确诊病例实施了积极的检测、隔离、接触者追踪和检疫策略。我们报告了 2020 年上半年越南北部 SARS-CoV-2 检测结果。
2020 年 1 月至 5 月期间，从越南北部的 14470 例疑似病例和接触者中采集了 15650 份上呼吸道标本。所有标本均通过实时 RT-PCR 检测 SARS-CoV-2。对阳性标本的个体每三天检测一次，直到两次检测均为阴性。对 81 例阳性标本进行培养。
在 14470 例检测个体中，确诊了 158 例（1.1%）SARS-CoV-2 感染病例；89 例为输入性病例，69 例与社区传播有关。大多数患者（122 例，77%）在两次检测后结果为阴性，而 11 例和 4 例在第三次和第四次采样时仍为阳性。从 81 份标本（36%）中分离出 SARS-CoV-2，Ct 值<30。在再次检测为阴性后又检测为阳性的 7 例患者 Ct 值>30，且培养结果为阴性。
在越南北部早期广泛检测 SARS-CoV-2 发现了很少的病例，结合其他积极的策略，可能显著控制了疫情。我们观察到病毒快速清除，清除后很少有阳性结果。大规模分子诊断检测是越南早期发现和控制 COVID-19 的关键部分，在广泛接种疫苗之前仍将是必要的。
