Ever wondered why some who test positive for coronavirus need a ventilator and experience more severe symptoms than others who are cured after showing very mild to moderate symptoms? The answer, researchers suggest, may be in the study of human genetics.
A report published by Bloomberg, The 23andMe study, looked at susceptibility rather than severity of illness and included 10,000 participants who had Covid-19. The research found that individuals with type O blood are between 9% and 18% less likely than individuals with other blood types to have tested positive for coronavirus.
Preliminary results from more than 750,000 participants suggests that the O blood group is especially protective against SARS-CoV-2, the virus that causes Covid-19. The findings echo other research that has indicated a link between variations in the ABO gene and coronavirus.
However, there was little difference in susceptibility among other blood types, the study found. When the researchers adjusted the data to account for factors like age and pre-existing illnesses and also restricted the data to only those with high-probability of exposure like healthcare workers, the findings were the same.
Can blood type play a role in severity of patient’s reactions to COVID-19?
Cardiologist Dr KK Agrawal says there is no proof to suggest a link between coronavirus and a certain blood group. He says, "Whenever there is a new disease like the novel coronavirus, people begin to find a link between the infection and the blood group."
Three studies say that O blood group is protective against the virus.
"But such studies can't be used as evidence because the data of 750,000 people (used by 23andMe) is not enough to prove anything, given the population of the country. These are just observation studies and not medical facts," says Dr. Agrawal.
He also added, "People with O blood group shouldn't think that they don't need to take any precautions."
Researchers have been grappling to find something in the genetics that may be responsible for some patients having severe reaction to the coronavirus while some recover with relatively milder symptoms of the coronavirus disease. Several other studies looking at both severity of illness and susceptibility to disease have also suggested blood type plays a role.
A research published last week prior to peer review suggested blood type may play a role in the severity of patients’ reactions to SARS-CoV-2. That study looked at the genes of more than 1,600 patients in Italy and Spain who experienced respiratory failure and found that having type A blood was linked to a 50% increase in the likelihood a patient would require a ventilator.