Canadian researchers suggest those with A or AB blood are more likely to suffer lung damage due to COVID-19. The researchers also noted that people with blood types A and AB did not have longer overall hospital stays.
The first of the two studies saw scientists look at health registry data from more than 473,000 people in Denmark who tested for Covid-19 and compared it to a control group of more than 2.2 million people from the general population, accounting for nearly 40 percent of the total Danish population.
It was observed that people with blood types A or AB were more likely to require mechanical ventilation and oxygen support post COVID infection.
A retrospective study of individuals tested for coronavirus showed that blood type O "may offer some protection against COVID-19 infection". Another study in April (pre-print and awaiting peer-review) found that among 1,559 coronavirus patients in New York City, a lower proportion than would be expected had Type O blood. It also found that people with blood group AB were the most likely to test positive for COVID-19 infection, followed by blood group B and then blood group A. In the first, researchers looked at some 473,654 people in Demark who were tested for COVID-19 between February and July and compared them with the general population of roughly 2.2 million people. After controlling for certain factors, they found fewer patients with blood type O, compared with patients with blood types A, B, and AB.
The research papers added evidence that there may be a connection between blood type and susceptibility to COVID-19 but the researchers stated that more studies need to be done to better understand why and what it means for patients. For example, people with type A blood produce different antibodies to people with blood type O. It's still not known, however, whether this has any significant effect on a person's ability to battle Covid-19.
The researchers examined data from 95 critically ill COVID-19 patients hospitalised in Vancouver.
However, both studies' authors note several limitations that warrant consideration, and suggest further research to confirm these findings and enhance scientists' understanding of blood type association to Covid-19 severity. They also found more patients with blood group "A" and "AB" required dialysis for kidney failure.
Your blood type may predict how severely you'd be affected by Covid-19, should you catch infection.