[blueash]

Originally Posted by Robbie0723

Estimated US Infection- and Vaccine-Induced SARS-CoV-2 Seroprevalence Based on Blood Donations, July 2020-May 2021 | Infectious Diseases | JAMA | JAMA Network

"Findings In this repeated cross-sectional study that included 1 443 519 blood donation specimens from a catchment area representing 74% of the US population, estimated SARS-CoV-2 seroprevalence weighted for differences between the study sample and general population increased from 3.5% in July 2020 to 20.2% for infection-induced antibodies and 83.3% for combined infection- and vaccine-induced antibodies in May 2021. Seroprevalence differed by age, race and ethnicity, and geographic region of residence, but these differences changed over the course of the study."

Certainly higher now...

Thank you for that link which has data up to May. As I wrote above the Red Cross stopped routine testing in June [although they are continuing some testing for future publication]. Regarding my supposition that donors may not represent the general population, this study in its limitations says:

vaccine-induced seroprevalence might be higher in blood donors than in the general population. For May 2021, among donations from donors with a known vaccine history, 73.3% were from donors who self-reported receiving a previous COVID-19 vaccine, compared with CDC estimates that 57.0% of US adults aged 18 years and older had received 1 dose or more of vaccine by May 2021