To date, predictors for developing a severe case of COVID-19 have included being in an older age group, being male, and those who have certain pre-existing health conditions like asthma, diabetes, and high blood pressure. A study in the New England Journal of Medicine that was published online June 17 revealed that an individual’s blood type might be another risk factor of who could get the sickest from the virus.
A multi-national group of researchers looked at the genes from 1980 patients with COVID-19 who had experienced respiratory failure from seven hospitals in Italy and Spain. They found that patients with blood type A were 50% more likely than people with other blood types to experience severe COVID-19 symptoms, including respiratory failure.
This is not the first time research results supporting the impact of blood type on COVID-19 have been reported. In March and again in April, study results were released on medRxiv that people with blood types in the A group were at a higher risk of testing positive for COVID-19 when compared with non-A-group types. Individuals with O type blood were in the lowest risk group.
MedRxiv is the preprint site that posts preliminary reports of research that have not been through the peer-review process. The medRxiv website states that the preprints that are available on their site, “should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.” The New England Journal of Medicine, on the other hand, is considered one of the most prestigious peer-reviewed journals available.
What Is Blood Type Based On?

Blood type is based on whether or not a person has certain molecules or proteins called antigens on the surface of their red blood cells. In the US, 40% of people have A-type blood, and 45% have O type blood. People with B type blood make up 11% of the population, and 4% are in the AB type group.
What Does This Research Mean?
“The hope is that these and other findings yet to come will point the way to a more thorough understanding of the biology of COVID-19. They also suggest that a genetic test and a person’s blood type might provide useful tools for identifying those who may be at greater risk of serious illness,” wrote Dr. Francis Collins on the National Institutes of Health (NIH) Director’s Blog. “More research is needed to pinpoint the precise underlying genes and mechanisms responsible.”
Dr. Collins stated on the NIH Director’s Blog that there are NIH research groups that have “recently launched a study to look for informative gene variants in 5,000 COVID-19 patients in the United States and Canada.”
As more information becomes available about this deadly virus, people at higher risk can take precautions to protect themselves by wearing masks, social distancing, and avoiding crowds.
Blood Type COVID Risk Factor — Sources
The New England Journal of Medicine – Genomewide Association Study of Severe Covid-19 with Respiratory Failure
NIH Director’s Blog – Genes, Blood Type Tied to Risk of Severe COVID-19
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