| Background:The COVID-19 pandemic has had a significant impact on human health,public health security and economic development.As researchers continue to deepen their understanding of SARS-COV-2,the spread of COVID-19 has been controlled through scientific epidemic prevention and control strategies,including strengthening screening of key populations,nucleic acid and antibody monitoring of SARS-CoV-2,and the development of SARS-CoV-2 vaccines.As acomplement technique,a reliable serological test is essential for diagnosing an individual’s history of infection and for evaluating the immunity after vaccination.Objective:1.The performance of three chemiluminescence(CLIA)methods was invesitigated in detecting SARS-CoV-2 IgM/IgG antibody.Afterward,the humoral immunity of SARS-CoV-2 infection was analyzed to support clinical diagnosis and epidemiological investigation.2.The results of viral neutralization test(VNT)was used as a criteria,the diagnostic accuracy of three chemiluminescence assays(CLIA)and two enzymed-linked immunosorbent assays(ELISA)was evaluated.CLIA was applied to investigate the protective neutralization antibody reaction kinetics in real world vaccinators.Methods:1.A total of 45 cases of COVID-19 infected patients,60 cases of recovered patients and 100 cases of healthy controls were recruited.Peripheral blood of patients was collected to obtain serum and evaluate the precision,functional sensitivity,linearity and accuracy of Axceed,iFlash and Maglumi chemiluminescence(CLIA)IgM and IgG kits.In addition,three CLIA and Novel Coronavirus nucleic acid tests were used to study the antibody response dynamics before and after SARS-CoV-2 infection.2.SARS-CoV-2 vaccinators(n=164)were recruited,then the serum SARS-COV-2 antibody detection was conducted with three CLIA(Axceed,iFlash,Ecl)and two ELISA(Yaneng,cPass)kits.The consistency and correlation of CLIA and ELISA results was performed with VNTresults.Axceed Kit,met the detection demand,was applied to monitor the antibody titervariation and positive conversion rate of SARS-CoV-2 IgM,IgG and neutralizing antibody in the population vaccinated with SARS-CoV-2vaccine within 6 months.Furthermore,a total of 732 healthy people were recruitedfrom the physical examination center of our hospital,the demographic data,the vaccines,and the neutralizing antibody titer as well as the reaction kinetics was analyzed in the real world after SARS-CoV-2 vaccination.Results:1.The SARS-CoV-2 IgMand IgG antibody detection kits of Maglumi and iFlash had the best analytical sensitivity,while the SARS-CoV-2 IgM and IgG antibody detection kits of Axceed had better linear analysis performance.The sensitivity of Axceed,iFlash and Maglumi kits for IgM antibody detection was 68.0%,64.9%and 63.9%,and the specificity was 99.0%,96.0%and 100%,respectively.The sensitivity and specificity of IgG antibody were 85.6%,97.9%and 94.8%,respectively.ROC curve analysis showed that the diagnostic capability of all kits was greater than 0.9.Of the 38 recovered patients,94.7%had an effective immune response,with the largest proportion of positive serum IgM and IgG antibodies(42 days after onset),followed by a single serum-positive IgG in the antibody spectrum(50 days after onset).2.Compared withVNT,the sensitivity and specificity of the five rapid NAb detection kits(Axceed,iFlash,Yaneng,cPass and Ecl)ranged from 100%,86%,84%,84%and 92%,respectively,showing high correlation(Kappa values were 1.00,0.80,0.78,0.78 and 0.89,respectively).In particular,the Axceed kit performed best for the real-world analysis of changes in antibody levels for SARS-CoV-2 vaccination.At present,BBIBP-CorV(76.3%)and Sinovac CoronaVac(20.5%)are the main vaccination types in Shenzhen.At 28 days after initial vaccination,the sero-positive rates of IgM,IgG and NAb are 6%,4%and 13%,respectively.The positive rates were 14%,65%and 97%,respectively,28 days aftersecond vaccination.Six months after second vaccination,the NAb positive rate remained at 66%.Conclusion:Different brands of antibody kits have different test capabilities,but their performance can meet the basic needs of SARS-CoV-2 immunological detection.IgM and IgG antibodies are produced afterSARS-CoV-2 infection,with IgM levels peaking 20～30 days after symptom onset and IgG levels peaking 31～60 days after symptom onset.The BBIBP-CorV vaccine induces a neutralizing antibody response in individuals that lasts at least 6 months after secondary vaccination.Therefore,serum antibody monitoring can provide a reference for whether an individual needs enhanced immunization.Figure 12,Table 8,Reference 42... |
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