Analysis of serological surveillance results of CO VID-19 in community populations in Nantong City
Objective To understand the variation characteristics of serum COVID-19 specific antibody levels in community populations,and provide a scientific basis for preventing of reinfection.Methods Chongchuan District,Rudong County,and Qidong City were selected as the monitoring points,and the three rounds of surveillance were carried out in December 2022,March and May 2023,respectively,with the number of sera collected in each monitoring point not less than 400 people each time.Immunoglobulin M(IgM),immunoglobulin G(IgG),and immunoglobulin A(IgA)to S protein were detected by chemiluminescence assay.SPSS 20.0 software was used for collated and statistical analysis of data.The analysis of variance(F-test)was used to compare the mean of two or more samples,and the Chi-square test was used to compare the count data.Results A total of 854 people were positive for IgG in the first round of surveillance,the positive rate was 69.09％.Of these,292 cases(23.62％)were infected recently.Two hundred and sixty-three people IgA-positive,the positive rate of IgA was 21.28％.In the second round of surveillance,41 people were positive for IgM,the positive rate was 3.39％,and 1 108 people were positive for IgG,the positive rate was 91.57％.In the third round of surveillance,10 people were positive for IgM,the positive rate was 0.84％.One thousand and eighty-three people were positive for IgG,with a positivity rate of 90.48％.Six hundred and ninety-eight people were positive for IgA,with a positivity rate of 58.31％.There was statistically significant difference in IgM positivity rate between the second and third rounds of surveillance(x2=18.910,P＜0.001).The positive rate of IgG differences in three rounds of surveillance was significantly different(x2=286.834,P＜0.001).The positive rate of IgA differences in the first round and the third round of surveillance was statistically significant(x2=2 433.000,P＜0.001).Conclusion In December 2022,23.62％of the population in Nantong City show recent infection with the SARS-CoV-2,with a higher infection rate in the main urban area population,young children,and primary school students.The positive rate of IgG peakes in March 2023,and decreases slightly in May 2023,however it still maintains a high level,indicating that antibody response to IgG can last for nearly 6 months,and epidemic surveillance and immunization should continue to be strengthened.
Community populationIgMIgGIgACOVID-19SurveillanceAnalysis
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