Association of ABO Blood Type with Infection and Severity of COVID-19 in Inpatient and Longitudinal Cohorts
Authors: Eatz Tiffany Alyssa , Mantero Alejandro Max Antonio , Williams Erin Caitlin , Cash Charles Joseph , Perez Nathalie Elisabeth , Cromar Zachary James , Hernandez Adiel , Cordova Matthew Moses , Godbole Neha Pradyumna , Anh Le Pham , Lin Rachel Rebecca , Luo Sherry , Patel Anmol Bharat , Abu Yaa Fosuah , Pallikkuth Suresh , Pahwa Savita G 
Published: August 2023

Introduction: The objectives of this study were to (1) investigate the association between human blood type and COVID-19 infection in both inpatient and longitudinal populations at our institution in South Florida and (2) identify the association between blood type and severity of COVID-19 infection via presence of cellular biomarkers of severe infection in hospitalized individuals.

Methods: This study consists of (1) a single-center retrospective analysis of 669 of 2,741 COVID-19 positive screened patients seen from January 1, 2020 until March 31, 2021 at the University of Miami Emergency Department (ED) who tested positive for COVID-19 infection and had a documented ABO blood type and (2) a longitudinal SARS-CoV-2 immunity study (“CITY”) at the University of Miami Miller School of Medicine consisting of 185 survey participants. COVID-19 outcome rates and 95% confidence intervals were calculated for each ABO blood type and Rh group using Chi-squared tests for categorical and ANOVA for continuous variables in the inpatient cohort and Chi-squared tests for the longitudinal cohort, all executed in R studio.

Results: Our inpatient cohort had a mean age of 53.6 (± 17.9) years with 48% males and 52% females. When compared to patients with other blood types, those with O- demonstrated less risk of developing COVID-19 pneumonia (26.7% for O- vs. 69.2% for type A-, 56.5% for A+, 71.4% for AB+, 53.7% for B+, 51.5% for O+, p-value= 0.003 via Chi-squared test) and decreased mortality due to COVID-19 infection (17.0% mortality for O vs. 26.3% for A, 29.2% for B, p-value= 0.012 via Chi-squared test). Blood type O- demonstrated less elevated levels of LDH than did other blood types (p-value= 0.001, ANOVA) and a higher frequency of clinically accepted baseline levels of troponin (0.04 ng/mL) (p-value= 0.026, ANOVA) (Figure 1).

Most of the longitudinal cohort was ABO blood grouping type O (47% (87/185)), with 33.5% type A, 14.1% B, and 5.4% AB. Most individuals were Rh positive (85.9%). There was no significant association found between COVID status (infection vs. non-infection) and ABO (Chi-squared test (3, N = 185) = 1.8, p = 0.6) or Rh (Chi-squared test (1, N = 185) = 0.16, p = 0.7) blood typing. Nearly all participants had been vaccinated (95.1% (176/185)), with a majority reporting primary vaccination with Pfizer (57.8% (107/185)), followed by Moderna (33% (61/185)), and Johnson &amp; Johnson (4.3% (8/185)). 8 participants (4.3%) were unvaccinated.

Conclusions: In an inpatient setting, blood type O sustained less risk of COVID-19 mortality and O- demonstrated less risk of developing COVID-19 pneumonia. In a longitudinal setting, there was no association found between blood type and COVID-19 severity. As the novelty of COVID-19 infection declines with time, further studies on risk-stratification by blood type are encouraged.