People with O blood type are less likely to contract the SARS-CoV-2, the virus that causes COVID-19, new research suggests.
However, blood types A and AB are at most risk and vulnerable to the infection. Two separate studies published in the journal Blood Advances on Wednesday, October 14 indicated that people with blood type O are also at lower risk of developing severe symptoms, including organ complications.
The studies were aimed at reasoning why the coronavirus is fatal for some, while others don't even get to know if they have had it.
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.
In the first study, researchers compared Danish health registry data from over 473,000 individuals tested for COVID-19 to data from a control group of more than 2.2 million people from the general population.
Among the Covid-19 positive, they found fewer people with blood type O and more people with A, B, and AB types. The study suggests that people with blood types A, B, or AB may be more likely to be infected with Covid-19 than people with type O.
The researchers did not find any significant difference in rate of infection between A, B, and AB types. "It is very important to consider the proper control group because blood type prevalence may vary considerably in different ethnic groups and different countries," said study author Torben Barington from the University of Southern Denmark.
In the second study, scientists examined 95 critically ill coronavirus patients in a hospital in Vancouver. They discovered that blood types A and AB were at a greater risk of severe symptoms than the O or B blood types.
The researchers noted that patients with these blood types (A and AB) were more likely to be put on mechanical ventilation, indicating that they had higher rates of lung injury from the virus - and dialysis from kidney failure. These patients were more prone to organ dysfunction or failure due to coronavirus.
Lead author of the study, Dr Mypinder Sekhon, of the University of British Columbia, said: "The unique part of our study is our focus on the severity effect of blood type on COVID-19."
Meanwhile, the scientists noted in the study, "We observed dis lung and kidney damage, and in future studies, we will want to tease out the effect of blood group and COVID-19 on other vital organs. Of particular importance, as we continue to traverse the pandemic, we now have a wide range of survivors who are exiting the acute part of COVID-19, but we need to explore mechanisms by which to risk stratify those with longer-term effects."