738例新型冠状病毒肺炎病例密切接触者核酸筛查结果分析

Nucleic acid screening results of 738 close contacts of coronavirus disease 2019

目的了解新型冠状病毒肺炎(简称新冠肺炎)病例密切接触者新型冠状病毒核酸检测及血常规结果。方法选取2020年2月11-23日某定点隔离酒店内738例新冠肺炎病例密切接触且无明显临床症状的医学观察人员,采集其鼻咽拭子进行新型冠状病毒核酸检测,采集血标本进行血常规检测,并观察至隔离期结束。结果 738例医学观察人员新型冠状病毒核酸检测阳性70例(9.49%),阴性664例(89.97%),可疑4例(0.54%),其中首次新型冠状病毒核酸检测阳性52例,可疑28例,阴性658例;对28例结果可疑者隔日重新采样检测,18例阳性,6例阴性,4例仍可疑(二次采样后观察期结束转至指定隔离观察点)。所有新型冠状病毒核酸检测阳性及可疑医学观察人员,血常规白细胞计数均正常,仅2例淋巴细胞计数减少。在第一个14 d观察期内,738例医学观察人员40例(5.42%)发病,其中70例新型冠状病毒核酸检测阳性者,42.86%(30例)出现发热、咳嗽、气促等临床症状;664例新型冠状病毒核酸检测阴性者,1.51%(10例)出现症状。所有确诊病例转至定点医院继续治疗;第一个观察期结束时,新型冠状病毒核酸检测未转阴者、结果仍可疑者送至指定隔离点继续观察。继续观察期中4.54%(2/44)出现症状被确诊,随即转至定点医院治疗;余下观察者新型冠状病毒核酸检测全部转阴。整个集中隔离期发病率为5.69%(42/738)。结论新冠肺炎病例密切接触者新型冠状病毒核酸检测阳性人员中,潜伏期感染者所占比例较高,亦存在一定比例的无症状感染者,应尽早识别、诊断。

Objective To understand results of nucleic acid test of 2019-nCoV(SARS-CoV-2) and blood routine examination of persons who had close contact with coronavirus disease 2019(COVID-19) cases.Methods 738 persons who were under medical observation in a designated isolation hotel from February 11 to 23, 2020 due to close contact with COVID-19 cases but without symptoms were selected, nasopharyngeal swabs were taken for 2019-nCoV nucleic acid test, and blood specimens were taken for blood routine detection, these persons were observed untill the end of isolation period.Results Among 738 persons who were under medical observation, 70(9.49%) were positive for nucleic acid test of 2019-nCoV, 664(89.97%) were negative, and 4(0.54%) were suspected;in the initial nucleic acid test of 2019-nCoV, 52 persons were positive, 28 were suspected, and 658 were negative;28 cases with suspected results were resampled the next day, 18 were positive, 6 were negative, and 4 were still suspected(After the second sampling, the observation period ended and these persons were transferred to the designated isolation observation place). Among all persons with positive nucleic acid test of 2019-nCoV and suspected persons under observation, white blood cell(WBC) count were all normal in blood routine, only 2 cases showed decreased lymphocyte count. During the first 14-day observation, among 738 medical observed persons, 40(5.42%) had COVID-19, 70 of whom were positive in nucleic acid test for 2019-nCoV, 42.86%(n=30) had fever, cough, shortness of breath and other clinical symptoms;among 644 persons with negative nucleic acid test, 1.51%(n=10) developed symptoms. All confirmed cases were transferred to designated hospitals for further treatment;at the end of the first observation period, those who did not turn negative for nucleic acid test of 2019-nCoV and those who still had suspected results were sent to the designated isolation place for continuous observation. During continuous observation period, 4.54%(2/44) developed symptoms and were confirmed with COVID-19, and were send to a designated hospital for treatment;the rest of the observed persons all turned negative in nucleic acid for 2019-nCoV detection. Incidence was 5.69%(42/738) during the whole isolation period.Conclusion Among persons with positive nucleic acid test of 2019-nCoV due to close contact with COVID-19 cases, proportion of latent infection is high, and there is a certain proportion of asymptomatic infected persons, which should be identified and diagnosed as early as possible.