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

JAMA Network ^ | September 2, 2021 | Jefferson M. Jones, MD, MPH

[Grandpa Drudge]

Key Points

Question Based on blood donations in the US from July 2020 through May 2021, how did infection- and vaccine-induced SARS-CoV-2 seroprevalence vary over time by demographic group and by geographic region?

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.

Meaning Based on a sample of blood donations in the US from July 2020 through May 2021, estimated SARS-CoV-2 seroprevalence increased over time and varied by age, race and ethnicity, and geographic region.

Importance People who have been infected with or vaccinated against SARS-CoV-2 have reduced risk of subsequent infection, but the proportion of people in the US with SARS-CoV-2 antibodies from infection or vaccination is uncertain.

Results Among 1 443 519 specimens included, 733 052 (50.8%) were from women, 174 842 (12.1%) were from persons aged 16 to 29 years, 292 258 (20.2%) were from persons aged 65 years and older, 36 654 (2.5%) were from non-Hispanic Black persons, and 88 773 (6.1%) were from Hispanic persons. The overall infection-induced SARS-CoV-2 seroprevalence estimate increased from 3.5% (95% CI, 3.2%-3.8%) in July 2020 to 20.2% (95% CI, 19.9%-20.6%) in May 2021; the combined infection- and vaccination-induced seroprevalence estimate in May 2021 was 83.3% (95% CI, 82.9%-83.7%). By May 2021, 2.1 SARS-CoV-2 infections (95% CI, 2.0-2.1) per reported COVID-19 case were estimated to have occurred.

[blueplum]

not really - only 20% ‘natural’ wild immunity - the rest are ‘natural ‘vaccinated immunity. Another point - immunity from wild covid doesn’t always mean immunity from Delta or the variants as ‘wild’ immunity is exposure-dependent, lower exposure level, less immunity. More exposure that results in hospitalization equals more immunity :)

[blueplum]

Thanks Grandpa Drudge

Here’s the original thread for more comments:
https://freerepublic.com/focus/f-chat/3991854/posts

and for even more comments, another discussion thread here:
https://freerepublic.com/focus/f-bloggers/3991986/posts

[lonestar67]

Empirical studies show that wild or natural immunity makes individuals 27 times less likely to contract Delta variant.

I would say that is robust and vastly superior to vaccine based immunity.

20 percent is also the absolute minimum observed in the blood supply sample. It could be much higher and easily toward 40%.

[Grandpa Drudge]

Exactly right, immunity as a result of recovery from the natural infection is far superior to vaccine induced immunity in 2 ways. Its much stronger, and it lasts much longer (years vs months). And if you believe there might be unexpected long term risks from the vaccine itself (as I do) you might choose to risk the disease rather than the vaccine.

[rarestia]

They were just giving advice on the platelet donation. They try to remain neutral given the clientele.