Susceptibility to a Covid-19 infection can vary depending on the blood group: people with type O may have the lowest risk, while those with A and AB may have a higher risk of severe clinical conditions, according to the findings of two published studies in Blood Advances magazine.
In one of the published research, it is suggested that people with blood type O may have a lower risk of Covid-19 infection and, of contracting the disease, a lower probability of serious results, including complications in the organs, according to a note from the American Society of Hematology.
To reach these conclusions, the researchers compared data from the Danish health registry of more than 473,000 people who were tested for Covid-19 with data from a control group of more than 2.2 million individuals from the general population.
Among those who tested positive for Covid-19, they found fewer people with blood type O and more people with types A, B, and AB; the researchers found no significant difference in the infection rate between types A, B, and AB.
In another retrospective study, scientists found that people with blood groups A or AB seem to show a greater severity of the disease than people with blood groups O or B.
In this case, to arrive at these results, the researchers examined data from 95 critically ill hospitalized patients in Vancouver, Canada. Thus, they found that those with blood groups A or AB were more likely to require mechanical ventilation, suggesting that they had higher rates of Covid-19 lung injuries. They also observed that more patients with blood groups A and AB required dialysis for kidney failure.
Together, these findings suggest that patients of these two blood groups may be at greater risk of organ dysfunction or failure due to Covid-19 than people with blood group O or B, the authors summarize.
Although these papers add evidence of an association between blood type and vulnerability to Covid-19, the authors believe that more research is needed to better understand why and what it means for patients.