ABSTRACT
OBJECTIVE: To investigate the immune antibodies in blood specimens of 95 health care workers vaccinated with inactivated 2019-nCoV vaccines and explore the rules and characteristics of production of antibodies after vaccination. METHODS: From Oct 2020 to Jul 2021, the venous blood specimens were collected from 95 health care workers of the 305 Hospital of PLA after the injection of 2 doses of 2019-nCoV vaccines fo30 days, 65 days, 91 days, 6 months and 9 months. SARS-CoV-2 immunoglobin(Ig) M, IgG and titers of neutralizing antibodies and total antibodies were detected by chemiluminescence immunoassay, the results of antibody tests were dynamically analyzed, the immune durability of the antibody, influencing factors and correlation were determined. RESULTS: Almost all of the subjects produced IgG, neutralizing antibody and total antibody, some subjects retained high level of IgM titer. Smoking could affect the production of total antibody. The subjects of the low body weight group produced higher level of IgG, and there was no significant difference when the weight was over 60 kg. The titers of the four types of antibodies decreased significantly at the following time points, and the positive rates of all the antibodies were less than 50% except for IgG after the vaccination for 9 months. CONCLUSION: Specific IgM and IgG, neutralizing antibody and total antibody can be produced after the 2-doses vaccination of inactivated 2019-nCoV vaccines. But the titers and positive rates of the antibodies decrease with time, which means the protective effects on the body decrease. Therefore, in order to improve the autoimmunity against novel coronavirus, one booster vaccination of an inactivated 2019-nCoV vaccine will be necessary after the 2 doses of vaccination for 6 months.