Tu179 - Longitudinal Analysis After sars-cov-2 Infection and Vaccination in LA-SPARTA: A Cohort of High-risk Individuals

Eduardo Valli – Pathology and Laboratory Medicine – University of California, Los Angeles; Donna Phan Tran – Division of Infectious Diseases – Lundquist Institute at Harbor-UCLA Medical Center; Evelyn Flores – Division of Infectious Diseases – Lundquist Institute at Harbor-UCLA Medical Center; Deborah Kupferwasser – Division of Infectious Diseases – Lundquist Institute at Harbor-UCLA Medical Center; Harry Pickering – Pathology and Laboratory Medicine – University of California, Los Angeles; Ying Zheng – Pathology and Laboratory Medicine – University of California, Los Angeles; David Gjertson – Pathology and Laboratory Medicine – University of California, Los Angeles; Ted Ross – Infectious Diseases – University of Georgia; Joanna Schaenman – Medicine – University of California, Los Angeles; Loren Miller – Medicine – University of California Los Angeles; Michael Yeaman – Medicine – University of California, Los Angeles; Elaine reed – Pathology and Laboratory Medicine – University of California, Los Angeles

Abstract Text: The correlates of risk and immune protection against SARS-CoV-2 infection and vaccination response are still largely unclear. Thus, we prospectively enrolled 200 participants with a high risk of SARS-CoV-2 occupational exposure, aiming to longitudinally analyze participant exposure risks, vaccination/infection status, and the the immune response to vaccination and natural infection. Symptoms of participants were assessed at 3, 6, and 12 months, along with blood and saliva collection. Quantitative ELISA assay was used to assess the serological response to the SARS-CoV-2 spike holoprotein (S), S-receptor binding domain (RBD) and nucleocapsid protein (NP). We found that 40 of 200 (20%) participants were infected via serology. No different in the infection incidence was noted in healthcare and non-healthcare occupations. 79.5% of infected participants seroconverted for NP, with 11.5% unaware they had been infected. The antibody response to S was greater than to RBD. Importantly, participants of Hispanic ethnicity had 2-fold greater incidence of infection despite vaccination. Booster vaccination significantly increased the quality of RBD-specific responses to variant spike proteins compared to the initial vaccination series. No differences in quality were found if a participant was boosted via vaccination or natural infection, via avidity analysis. Collectively, our results indicate that antibody quality and holoprotein response may reveal meaningful determinants of protection beyond RBD antibody titer alone. We also note that determinants of SARS-CoV-2 infection may include race/ethnicity, and remain independent of comorbidity and humoral response in this cohort.