376例新冠肺炎恢复期与灭活疫苗接种后人群的血清抗体检测结果分析

Serum antibody results among 376 COVID-19 patients in convalescence and inactivated vaccine recipients

目的对愈后半年及灭活疫苗接种后1至9个月人群IgM和IgG抗体应答的特点进行分析。方法以灭活疫苗免疫后1、3、6、9月四个不同月份人群血清共336例,新型冠状病毒肺炎(COVID-19)愈后6个月的恢复期血清40例作为样本盘,分别使用BGI(中国北京)、WANTAI(中国北京)两种商品化SARS-CoV-2 IgM抗体ELISA检测试剂盒以及KEWEI(中国北京)、WANTAI(中国北京)两种IgG抗体ELISA检测试剂盒进行IgM和IgG抗体检测。结果疫苗免疫后1个月IgM抗体阳性率分别为40%(BGI)与23%(WANTAI);在免疫后9个月血清中仍可检出IgM抗体阳性,为2.1%(1/48)。免疫后1个月IgG抗体阳性率均为100%,几何平均滴度(GMT)分别为256.3(KEWEI)与152.4(WANTAI);免疫后6个月IgG抗体阳性率与GMT分别为96.6%、60.25(KEWEI)及85.2%、15.79(WANTAI);灭活疫苗接种后IgG抗体阳性率与GMT均随时间延长呈下降趋势。愈后6个月的恢复期血清IgM与IgG抗体阳性率分别为37.5%与97.5%,IgG抗体GMT为429.6(KEWEI)与121.3(WANTAI)。结论IgM抗体在COVID-19恢复后6个月人群及灭活疫苗接种后9个月人群中均检出,IgM检测阳性作为急性COVID-19感染诊断指标时要审慎解读。灭活疫苗接种后大部分人群IgG抗体阳性率维持时间长于半年,但其滴度低于自然感染后半年人群。

Objective To analyze IgM and IgG antibody responses among patients at 6 months after recovery and inactivated vaccine recipients(IVRs)at 1 to 9 months after vaccination.Methods A total of 336 serum samples from the IVRs at 1,3,6,and 9 months,and 40 serum of samples from convalescent coronavirus disease 2019(COVID-19)patients were used as the sample panels.Two commercial SARS-CoV-2 IgM ELISA kits from BGI(Beijing,China)and WANTAI(Beijing,China)and two IgG ELISA kits from KEWEI(Beijing,China)and WANTAI(Beijing,China)were used for IgM and IgG antibody detection.Results The antibody positive rates of IgM were 40%(BGI)and 23%(WANTAI)among IVRs at 1 month after vaccination while IgM can be still detected in one serum sample(2.1%,1/48)of IVRs at 9 months after vaccination.The positive rate of IgG in IVRs at 1 month after vaccination was 100%and the geometric mean titers(GMT)were 256.3(KEWEI)and 152.4(WANTAI),respectively.The positive rates of IgG antibody and the GMT among IVRs at 6 months were 96.6%and 60.25(KEWEI),85.2%and 15.79(WANTAI),respectively.The positive rates of IgG and the GMT among IVRs showed trend of decreasing with time after vaccination.For the patients in convalescent at 6 months,the positive rates of serum IgM and IgG antibodies were 37.5%and 97.5%,respectively,and the GMT of IgG were 429.6(KEWEI)and 121.3(WANTAI),respectively.Conclusions IgM antibody was detected among patients at 6 months after recovery and IVRs at 9 months after vaccination.IgM positive as a diagnostic indicator for acute COVID-19 infections should be interpretated with precaution.The period of IgG positive status in most IVRs were more than half a year,but the titers were lower than that of patients 6 months after natural infection.