Your Risk Of Severe Covid-19 May Be Affected By Blood Type

August 22, 2020

A new study suggests that genes associated with certain blood types may increase the risk of severe COVID-19 infection, leading to respiratory failure and death.

The study authors found that people with blood type A were 50 percent more likely to develop severe COVID-19 symptoms and respiratory failure than people with other blood types. In contrast, people with blood type O had a 50 percent lower risk of developing COVID-19 – a disease caused by a novel coronavirus – or symptoms severe enough to require oxygen or a ventilator.

Scientists used genome-wide association studies to find a link between blood type and COVID-19 results. According to the National Human Genome Research Institute, by looking at single-letter changes in many genes in large populations, researchers were able to identify genetic variants that may be associated with disease risk.

As previously reported by Live Science, two previous studies have hinted at the possibility of a link between blood type and risk factors for COVID-19. Different research teams have found that people with blood type A have a higher risk of developing COVID-19 than those with other blood types, while those with blood type O are less likely to contract the disease.

However, the studies were published on the preprint database medRxiv – March 27 and April 11 – and were not peer-reviewed.

In the new study, the researchers identified two regions of the genome where genetic variation is associated with severe cases of COVID-19 and a higher risk of death; in these regions, there is a gene that determines blood type. Their findings were published online June 17 in the New England Journal of Medicine.

The researchers sampled the genomes of 1,610 COVID-19 patients and more than 1,300 healthy blood donors from Italy and Spain and analyzed single-letter changes in more than 8 million DNA codes called single-nucleotide polymorphisms, or SNPs (pronounced “snips”). According to the U.S. National Library of Medicine, there are millions of SNPs sprinkled throughout a person’s genome that can serve as markers for locating disease-associated genes.

The study authors identified regions of the genome associated with respiratory failure from COVID-19 – symptoms severe enough to require supplemental oxygen or the use of a mechanical ventilator. One signal originated from a region that included genes associated with the immune response of the lungs. The other signal came from a region that also encodes blood group, allowing the researchers to identify “the potential involvement of the ABO blood group system in COVID-19,” they wrote in the study. This link suggests that blood type may be associated with the severity of respiratory symptoms.

Another region they identified contains six genes, some of which interact with the ACE2 receptor targeted by SARs-CoV-2, while others are associated with chemicals that interact with immune cells in the lungs. It is unclear which of these genes play a role in disease susceptibility.

“Genetic testing and a person’s blood type may provide useful tools to identify those who may be at greater risk for serious disease,” said NIH Director Francis Collins in a statement about the new study.

“Hopefully, these and other findings that have yet to emerge will point the way to a more thorough understanding of the biology of COVID-19,” Collins said.

However, many other factors also determine the extent to which an individual is affected by a disease.

Underlying health conditions such as heart disease, chronic lung disease and diabetes greatly increase the chances of developing COVID-19 or dying from it. In fact, while older adults are often considered more susceptible to serious cases of COVID-19, Live Science previously reported that this may be explained by the chronic medical conditions that often accompany aging.