Association of ABO- and Rh-Type Blood Groups with SARS-CoV-2 Infection or Severe COVID-19 Disease

Type O and Rh- blood types may have a slightly lower risk of SARS-CoV-2 infection or severe COVID-19 disease.

https://doi.org/10.7326/M20-4511

Commentary

This study was conducted to determine if ABO and Rh blood types are associated with the risk of SARS-CoV-2 infection. The study was a population-based cohort study and included all adults and children who underwent SARS-CoV-2 testing between January 15 and June 30, 2020 in the Ontario region, Canada.

The study included a total of 225,556 individuals, with a mean age of 54 years, and an aRR of 0.88 for SARS-CoV-2 infection of O blood type versus A, AB, and B blood types. (95% CI, 0.84 to 0.92; ARD, -3.9/1000 [CI, -5.4 to -2.5]). . 

In addition, rhesus-negative (Rh-) blood types were protective against SARS-CoV-2 infection (aRR, 0.79 [CI, 0.73 to 0.85]; ARD, -6.8 per 1000 [CI, -8.9 to -4.7]), and especially those O-negative (O-) could be much more protective . (aRR, 0.74 [CI, 0.66 to 0.83]; ARD, -8.2 per 1000 [CI, -10.8 to -5.3]).

This indicates that the risk of severe COVID-19 disease and death associated with type O blood group is low compared to all others. (aRR, 0.87 [CI, 0.78 to 0.97]; ARD, -0.8/1000 [CI, -1.4 to -0.2])

A limitation of these results, however, is that individuals who died suddenly from severe COVID-19 illness may not have been tested for SARS-CoV-2.