COVID-19 Serological Study in Non-infected Vaccinated Subjects: Differences among Age, Sex, and Vaccine Brand

Abstract

Objective: To evaluate IgG antibody levels against SARS-CoV-2 in non-infected vaccinated subjects among vaccine brand, sex, and age. Methods: Abbott’s AdviseDx SARS-CoV-2 IgG II immunoassay was used to measure IgG levels within 6-9 months after the second dose vaccination; level >50 AU/mL was classified as a positive test. Results: Data of 183 non-infected vaccinated subjects was analyzed according to the vaccine brand, time after second vaccination, sex, and age. Bivariate analysis showed that receiving the Moderna brand vaccine, being female, and younger were associated with higher antibody levels, p<.001. Conversely, no differences were observed between the IgG antibody levels against SARS-CoV-2 and time after second vaccination (6-7 months as compared to 8-9 months), p=.49. Conclusion: After six to nine months post-vaccination, receiving the Moderna vaccine, being female, and being younger were significantly associated to higher IgG antibody levels to SARS-CoV-2 in non-infected vaccinated subjects.