The ABO gene is highly polymorphic, and ABO blood groups are distributed differently across ancestries and geographies. The smaller sample sizes and retrospective, observational nature of many prior studies, in addition to their striking heterogeneity of ABO associations with disease susceptibility and severity, could be due to chance variations, publication bias, differences in genetic background, geography and environment, and viral strains. With contrasting reports from China, 1 Europe, 2, 3 Boston, 4 New York, 5 and elsewhere, 6 we embarked on a large, prospective case-control study that included more than 11вЂЇ000 individuals who were newly infected with SARS-CoV-2, and we found no ABO associations with either disease susceptibility or severity. Analyses restricted to White race produced similar results ( Table 2). Similarly, types B and AB were not associated with worse outcomes than type O. Compared with type O blood, type A was not associated with increased viral positivity (OR, 0.97 PвЂ‰=вЂ‰.11), hospitalization (OR, 0.89 PвЂ‰=вЂ‰.03), or ICU admission (OR, 0.84 PвЂ‰=вЂ‰.08) ( Table 2).

Blood type was not associated with disease susceptibility or severity, including viral positivity, hospitalization, or ICU admission ( Table 1). Non-White race, which included African American, American Indian or Alaskan Native, Native Hawaiian or Pacific Islander, Asian, and unknown or declined to answer, was associated with viral positivity (1592 individuals with positive results vs 6610 individuals with negative results) and hospitalization (556 patients hospitalized vs 1036 individuals not hospitalized). Admission to an ICU was also associated with male sex (426 men admitted to ICUs vs 725 men not admitted) and age (mean age among patients admitted to ICUs, 60.7 years vs 55.4 years in patients not admitted).

Among individuals with COVID-19, hospitalization was associated with male sex (1165 men hospitalized vs 1871 men not hospitalized) and age (mean age among hospitalized patients, 57.0 years vs 41.4 years among nonhospitalized individuals). Further demographic characteristics of the studied population and ABO blood group associations are shown in Table 1. Data were analyzed from November 20, 2020, to February 26, 2021.ДЄ total of 107вЂЇ796 individuals (mean age, 42.0 years 82вЂЇ875 women) who had been tested for SARS-CoV-2 infection were included in the study. Statistical significance was set at PвЂ‰=вЂ‰.006 for assessment of ORs because each set underwent 9 comparisons. P values were 2-sided, and statistical significance was set at PвЂ‰<вЂ‰.167 for each of the 3 primary comparisons. Odds ratios (ORs) between ABO groups were assessed by logistic regression adjusted for age, sex, and Rh factor. Analysis of variance assessed associations across ABO groups. Infectivity was determined by SARS-CoV-2вЂ“specific polymerase chain reaction testing of nasal swabs or saliva samples. We compared positive vs negative test results, hospitalized vs nonhospitalized patients, and intensive care unit (ICU) vs non-ICU patients. For individuals who underwent multiple tests, the first test with a positive result was chosen, otherwise the first test with a negative result was used. We searched this database for individuals who were tested for SARS-CoV-2 between March 3 and November 2, 2020, and had a recorded blood type. Intermountain Healthcare, a nonprofit, integrated health care system of 24 hospitals and 215 clinics in Utah, Idaho, and Nevada, generated a SARS-CoV-2 and COVID-19вЂ“specific electronic health records database. This study is reported following the Strengthening the Reporting of Observational Studies in Epidemiology ( STROBE) reporting guideline. The study was approved by the Intermountain Medical Center institutional review board with a waiver of consent because the study represented no more than minimal privacy risk to individuals. Our objective in this case-control study was to independently test whether blood type is associated with SARS-CoV-2 susceptibility and COVID-19 severity.

Shared Decision Making and Communication.

Scientific Discovery and the Future of Medicine.

Health Care Economics, Insurance, Payment.

Clinical Implications of Basic Neuroscience.Challenges in Clinical Electrocardiography.

Blood type and covid