Serological analysis of severe acute respiratory syndrome coronavirus 2-specific immunoglobulin G antibodies level in Henan Province / 中华传染病杂志

ABSTRACT

Objective:To analyze the specific immunoglobulin G (IgG) antibodies level in the population after the coronavirus disease 2019 (COVID-19) pandemic in Henan Province.Methods:A total of 5 178 peripheral venous blood samples were collected from 10 districts (counties) in Henan Province according to the national seroepidemiological survey program for COVID-19, and the method of cluster random sampling was adopted from March 6 to 15, 2023. Descriptive analysis was used for the basic data, history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, SARS-CoV-2 infection of the respondents. The specific IgG antibody of SARS-CoV-2 was detected using chemiluminescence method. Statistical analysis was performed by using rank sum test, Kruskal Wallis test, and Dunn′s test.Results:The overall positive rate of SARS-CoV-2-specific IgG antibody was 83.35%(4 316/5 178). There were statistically significant differences in the specific IgG antibodies against SARS-CoV-2 produced by people of different sexes, different ages, infected or not, vaccinated or not, and vaccinated with different doses of SARS-CoV-2 vaccine ( Z=3.60, H=195.32, Z=6.10, 18.08, H=382.70, respectively, all P<0.001). The specific IgG antibodies produced by unvaccinated+ uninfected group, unvaccinated+ infected group, vaccinated+ uninfected group, and vaccinated+ infected group were 3.54(0.98, 11.00), 60.65(2.33, 84.80), 133.00(59.80, 173.00), and 142.00(98.30, 176.00), respectively. And the difference was statistically significant( H=354.62, P<0.001). The specific IgG antibodies of uninfected people increased with the increase of inoculum times( H=287.00 and 98.48, both P<0.001). The specific IgG antibodies of people who were not infected with SARS-CoV-2 in the groups of whose interval from the last inoculation of SARS-CoV-2 vaccine to blood collection was less than three months, three to six months and more than six months were 171.86(156.04, 196.57), 71.71(17.08, 110.38) and 132.14(57.59, 172.25), respectively, and the difference was statistically significant ( H=19.93, P<0.001). Among them, the absolute difference between the less than three months group and the three to six months group was statistically significant ( Z=3.67, P<0.001), and the absolute difference between the less than three months group and the more than six months group was statistically significant ( Z=3.47, P<0.001). The specific IgG antibodies level in the less than three months group was the highest. Conclusions:There is a certain correlation between the number of SARS-CoV-2 vaccine doses and the specific IgG antibodies level in uninfected people. The specific IgG antibodies could maintain a high level for three months after immunization.