SARS-CoV-2 Convalescent Sera Binding and Neutralizing Antibody Concentrations 1 Compared with COVID-19 Vaccine Efficacy Estimates Against Symptomatic 2 Infection 3

21 Previous vaccine efficacy (VE) studies have estimated neutralizing and binding antibody 22 concentrations that correlate with protection from symptomatic infection; how these estimates compare 23 to those generated in response to SARS-CoV-2 infection is unclear. Here, we assessed quantitative 24 neutralizing and binding antibody concentrations using standardized SARS-CoV-2 assays on 3,067 25 serum specimens collected during July 27, 2020-August 27, 2020 from COVID-19 unvaccinated persons 26 with detectable anti-SARS-CoV-2 antibodies using qualitative antibody assays. Quantitative neutralizing 27 and binding antibody concentrations were strongly positively correlated (r=0.76, p<0.0001) and were 28 noted to be several fold lower in the unvaccinated study population as compared to published data on 29 concentrations noted 28 days post-vaccination. In this convenience sample, ~88% of neutralizing and 30 ~63-86% of binding antibody concentrations met or exceeded concentrations associated with 70% 31 COVID-19 VE against symptomatic infection from published VE studies; ~30% of neutralizing and 1- 32 14% of binding antibody concentrations met or exceeded concentrations associated with 90% COVID- 33 19 VE. These data support observations of infection-induced immunity and current recommendations 34 for vaccination post infection to maximize protection against symptomatic COVID-19.