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

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. Objective: To estimate trends in SARS-CoV-2 seroprevalence related to infection and vaccination in the US population. Design, Setting, and Participants: In a repeated cross-sectional study conducted each month during July 2020 through May 2021, 17 blood collection organizations with blood donations from all 50 US states; Washington, DC; and Puerto Rico were organized into 66 study-specific regions, representing a catchment of 74% of the US population. For each study region, specimens from a median of approximately 2000 blood donors were selected and tested each month; a total of 1 594 363 specimens were initially selected and tested. The final date of blood donation collection was May 31, 2021. Exposure: Calendar time. Main Outcomes and Measures: Proportion of persons with detectable SARS-CoV-2 spike and nucleocapsid antibodies. Seroprevalence was weighted for demographic differences between the blood donor sample and general population. Infection-induced seroprevalence was defined as the prevalence of the population with both spike and nucleocapsid antibodies. Combined infection- and vaccination-induced seroprevalence was defined as the prevalence of the population with spike antibodies. The seroprevalence estimates were compared with cumulative COVID-19 case report incidence rates. 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. Conclusions and Relevance: Based on a sample of blood donations in the US from July 2020 through May 2021, vaccine- and infection-induced SARS-CoV-2 seroprevalence increased over time and varied by age, race and ethnicity, and geographic region. Despite weighting to adjust for demographic differences, these findings from a national sample of blood donors may not be representative of the entire US population.

Strengthening the service continuum between transfusion providers and suppliers: enhancing the blood services network.

As the cost of health care increases, the focus on cost containment grows. The pressure to reduce costs comes at the same time the public focus is on ensuring a zero-risk blood supply. The blood supply has never been safer or more expensive. With the relative vanquishing of transfusion-transmitted diseases, noninfectious risks now exceed infectious risks. This has resulted in a call to refocus blood safety efforts on interconnected processes that link a unit of blood from its volunteer blood donor to the patient. Additional costs in the blood supply chain will create new pressures on an already taxed system that gets little additional reimbursement with each new safety initiative. Opposing interests have created a tenuous relationship between the blood supplier and the transfusion provider. This adversarial relationship does not benefit the ultimate stakeholder, the patient. It is time to create a service partnership that is built on access, cost, and quality. Initiatives must be undertaken at a local, regional, and national level. Locally, blood suppliers and transfusion providers must reevaluate policies that are focused on individual gain and reinvent policies that will reward improvements in the overall system and expand cooperative services. Regionally, both blood suppliers and transfusion providers need to consolidate services to gain cost and quality benefits without compromising the competitive nature of the industry. Nationally, the creation of a strategic plan will help ensure that a mutually beneficial relationship focused on the patient is created between the blood supplier and transfusion provider at all levels. Development of such a plan would benefit the transfusing and supplying parties by identifying areas of common interest and how each may facilitate the achievement of shared benefits.