Objective: To analysis effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy (combined screening strategy) for screenin the imported patients with COVID-19 in Xiamen. Methods: The study populations were overseas travelers arriving in Xiamen from March 17 to December 31, 2020, and overseas travelers who had quarantine outside Xiamen for less than 21 days from July 18 to December 31, 2020. Data were collected and analyzed on the timing of detection, pathways, and test results of the imported patients with COVID-19 after implementing combined screening strategy. Results: A total of 304 imported patients with COVID-19 were found from 174 628 overseas travelers and 943 overseas travelers from other cities. A total of 163 cases (53.6%) were diagnosed by multitime, multisite intensive nucleic acid testing after positive finding in total antibody testing. Among them, 27 (8.9%) were first positive for nucleic acid in 14 plus 7 day quarantine and 136 were first positive for nucleic acid in 14-day quarantine. Only 8 of these individuals were tested positive for nucleic acid after positive total antibody testing. The other 128 individuals were tested positive for nucleic acid after being negative for average 2.3 times (maximum of 6 times). Aditional 155 cases might be detected by using the combined "14 plus 7 day quarantine" and " nucleic acid plus total antibody testing" strategy compared with "14-day quarantine and nucleic acid testing" strategy, accounting for 51.0% of the total inbound infections. So the combined screening strategy doubled the detection rate for imported patients with COVID-19. No second-generation case caused by overseas travelers had been reported in Xiamen as of February 26, 2021. Conclusions: Xiamen's combined screening strategy can effectively screen the imported patients with COVID-19 who were first positive for nucleic acid after 14 day quarantine. Compared with "14 day quarantine and nucleic acid testing", the combined screening strategy improved detection rate and further reduced the risk of the secondary transmission caused by the imported patients with COVID-19.
目的： 评估厦门市实施入境人员“14+7隔离”与“核酸+总抗体筛查”策略（联合筛查策略）对发现境外输入性新型冠状病毒（新冠病毒）感染者的作用。 方法： 研究对象为2020年3月17日至12月31日厦门市入境人员、7月18日至12月31日外地隔离不足21 d的入境人员。收集和分析实施联合筛查策略后的境外输入性新型冠状病毒感染者的发现时间、路径和检测情况。 结果： 在174 628名入境人员和943名外地入境人员中，共发现304例境外输入性新冠病毒感染者，其中163例（53.6%）为总抗体阳性后经多次及多部位核酸检测确诊，27例（8.9%）在入境14 d后首次核酸阳性，136例入境“14 d”隔离期间首次核酸检测阳性，仅8例在总抗体阳性后首次核酸检测阳性，128例在平均2.3次（最高6次）核酸检测阴性后转为阳性。联合筛查策略比“14 d隔离+核酸筛查”策略估算多检出155例，占入境感染者总数的51.0%，提高检出率约1倍。截至2021年2月26日尚未发现厦门市入境人员引起的续发感染。 结论： 厦门市对入境人员实施联合筛查策略，可有效筛查入境14 d后转为核酸阳性的新冠病毒感染者，与“14 d隔离+核酸筛查”策略相比，有效提高检出率，降低境外输入引起续发传播的风险。.