Lyu Zhaoqing, Harada Sassa Mariko, Fujitani Tomoko, Harada Kouji H
Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Yoshida Konoe, Sakyo, Kyoto 6068501, Japan.
Diseases. 2020 Sep 23;8(4):36. doi: 10.3390/diseases8040036.
The number of COVID-19 patients in Japan is considered low, compared with U.S. and European countries. However, recent serological survey reported that several percent of population showed IgG positive to SARS-CoV-2. Specificity in the assays might influence the estimate, and possibility of overdiagnosis should be investigated. Serological tests for SARS-CoV-2 coronavirus were performed in pre-COVID-19 sera in Japan (400 healthy subjects in 2012-2015). Lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) showed 1.5% (6/400) and 1.75% (7/400) IgG positives, respectively. Among those false positive samples, only one sample was positive in both LFA and ELISA (0.25%; 95% CI: 0.006-1.39%). Possible bias from pooling method was examined by Monte Carlo method and the possibility was unlikely at low false positive rate. Previous surveys might overestimate COVID-19 seroprevalence in several populations of Japan. These false positives could be excluded by combination of different diagnostics. Nonetheless, the result of seroprevalence should be carefully interpreted in less prevalent areas.
与美国和欧洲国家相比，日本新冠肺炎患者数量被认为较少。然而，最近的血清学调查显示，有百分之几的人口对严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的IgG呈阳性。检测方法的特异性可能会影响估计结果，因此应调查过度诊断的可能性。在日本，对新冠肺炎疫情之前的血清样本（2012 - 2015年的400名健康受试者）进行了SARS-CoV-2冠状病毒的血清学检测。侧向流动分析法（LFA）和酶联免疫吸附测定法（ELISA）显示IgG阳性率分别为1.5%（6/400）和1.75%（7/400）。在那些假阳性样本中，只有一个样本在LFA和ELISA中均呈阳性（0.25%；95%置信区间：0.006 - 1.39%）。通过蒙特卡洛方法检验了合并方法可能产生的偏差，在低假阳性率情况下这种可能性不大。之前的调查可能高估了日本部分人群中新冠肺炎的血清流行率。通过不同诊断方法的组合可以排除这些假阳性结果。尽管如此，在流行率较低的地区，血清流行率的结果仍应谨慎解读。
