1356. "Correlates of protection against SARS-CoV-2 post-vaccine infections in the Prospective Assessment of SARS-CoV-2 Seroconversion (PASS) Study"
Authors: Goguet Emilie , Olsen Cara , Meyer William A , Ansari Sara , Conner Tonia , Powers John H , Coggins Si’Ana A , Wang Wei , Wang Richard , Illinik Luca , Edwards Margaret Sanchez , Jackson-Thompson Belinda , Hollis-Perry Monique , Wang Gregory , Alcorta Yolanda , Wong Mimi , Saunders David , Mohammed Roshila , Balogun Bolatito , Kobi Priscilla , Kosh Lakeesha , Bishop-Lilly Kimberly A , Cer Regina , Arnold Catherine , Voegtly Logan , Fitzpatrick Maren , Luquette Andrea , Malagon Francisco , Ortega Orlando , Parmelee Edward , Davies Julian , Lindrose Alyssa R , Haines-Hull Hannah , Moser Matthew , Samuels Emily C , Tso Marana S , Graydon Elizabeth , Malloy Allison M , Tribble David , Burgess Timothy , Campbell Wesley , Robinson Sara , Weiss Carol D , O’Connell Robert , Broder Christopher C , Pollett Simon , Laing Eric D , Mitre Edward 
Published: November 2023

Abstract

Background
We sought to determine pre-infection correlates of protection against SARS-CoV-2 post-vaccine infections.

Methods
Serum and saliva samples from 176 BNT162b2-vaccinated adults in the Prospective Assessment of SARS-CoV-2 Seroconversion study were collected between October and December 2021 and assessed for serum and saliva levels of ancestral (WT) SARS-CoV-2 Spike (S)-specific IgG and IgA binding antibodies (bAb), and serum levels of Omicron BA.1 subvariant S-specific IgG bAb using a multiplex microsphere-based immunoassay. Serum samples were also assessed for WT S-specific bAb by two commercial assays, and neutralization activity against D614G, Delta (617.2), and Omicron BA.1 and BA.1.1 subvariants using a lentiviral pseudovirus neutralization assay. After the fall 2021 visit, participants reported all positive PCR and/or antigen tests for SARS-CoV-2. Duration, severity, and type of symptoms, as well as risk exposures and adherence to precautionary measures, were assessed by questionnaires during the spring 2022 visit.

Results
Thirty-two participants (18.2%) developed post-vaccination infections (PVI) between December 7, 2021 and April 1, 2022. Pre-infection WT and BA.1 anti-S IgG bAb levels measured by MMIA and neutralizing titers (NT) against BA.1 and BA.1.1 were significantly higher in individuals that did not develop PVIs. WT anti-S IgG bAb levels greater than 5,000 binding antibody units/ml were associated with substantial protection against symptomatic PVI.

Conclusion
Anti-S IgG bAb levels (directed against either WT or BA.1) and NT IgG titers both serve as correlates of protection against symptomatic PVI, with high levels associated with both protection against symptomatic infection and reduced severity of disease in those who develop PVI. Results of this study also suggest that commercial assays for anti-S bAb may need to be reformatted to enable detection of higher maximum values for use as predictors of increased susceptibility to SARS-CoV-2 infection.

Disclosures
David Tribble, MD, DrPH, AstraZeneca: The IDCRP and HJF were funded to conduct an unrelated phase III COVID-19 monoclonal antibody immunoprophylaxis trial as part of US Govt COVID response Timothy Burgess, MD, MPH, AstraZeneca: The IDCRP and the Henry M. Jackson Foundation (HJF) were funded to conduct an unrelated phase III COVID-19 monoclonal antibody immunoprophylaxis trial Simon Pollett, MBBS, AstraZeneca: The IDCRP and the Henry M. Jackson Foundation (HJF) were funded to conduct an unrelated phase III COVID-19 monoclonal antibody immunoprophylaxis trial