Recent studies provide conflicting evidence on the persistence of SARS-CoV-2 immunity induced by mRNA vaccines. Here, we aim to quantify the persistence of humoral immunity following vaccination using a coronavirus antigen microarray that includes 10 SARS-CoV-2 antigens. In a prospective longitudinal cohort of 240 healthcare workers, composite SARS-CoV-2 IgG antibody levels did not wane significantly over a 6-month study period. In the subset of the study population previously exposed to SARS-CoV-2 based on seropositivity for nucleocapsid antibodies, higher composite anti-spike IgG levels were measured before the vaccine but no significant difference from unexposed individuals was observed at 6 months. Age, vaccine type, or worker role did not significantly impact composite IgG levels, although non-significant trends towards lower antibody levels in older participants and higher antibody levels with Moderna vaccine were observed at 6 months. A small subset of our cohort were classified as having waning antibody titers at 6 months, and these individuals were less likely to work in patient care roles and more likely to have prior exposure to SARS-CoV-2.
Keywords: SARS-CoV-2; antibodies; healthcare workers; mRNA; microarray; serology; vaccine.
Copyright © 2022 Hosseinian, Powers, Vasudev, Palma, de Assis, Jain, Horvath, Birring, Andary, Au, Chin, Khalil, Ventura, Luu, Figueroa, Obiero, Silzel, Nakajima, Gombrich, Jasinskas, Zaldivar, Schubl, Felgner, Khan and The Specimen Collection Group.