Patterns of Antibody Response to Severe Acute Respiratory Syndrome Coronavirus 2 Among 1.6 Million Blood Donors: Impact of Vaccination, United States, December 2020–June 2021
Roger Y. Dodd, Edward P. Notari, Jaye P. Brodsky, Gregory A. Foster, Meng Xu, Paula Saá, Susan L. Stramer
Abstract
From December 2020 to June 2021, 1654487 blood donors were tested for antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S1 protein, and 1028547 (62.17%) were reactive. A rapid increase in prevalence was due to vaccination. Among a subset of 1567446 donors, 729771 (46.56%) reported SARS-CoV-2 vaccination, of whom 633769 (86.84%) were S1-antibody reactive only in response to vaccination and 68269 (9.35%) were reactive to both S1 and nucleocapsid in response to prior infection; the remainder were not reactive to either antibody. Among the 837675 (53.44%) donors who did not report vaccination, 210022 (25.07%) had reactivity to both antibodies and 29446 (3.52%) to S1 only.