During the ongoing COVID-19 pandemic, many research companies are taking advantage of this disease to gather new information about the effects of the virus on someone’s health and even possible indicators in a person’s body to determine whether or not that person has a high chance of contracting it. Surprisingly, researchers are able to find evidence that one’s blood type could indicate one’s susceptibility towards the coronavirus. 

Based on the results from a study in Canada, people who have blood type O and B are less likely to contract the virus than people with blood type A and AB. In addition, data of critically ill COVID-19 patients, who are hospitalized in Vancouver, Canada, suggests that those who have blood type A and AB have a higher chance of needing ventilators and extensive care than other blood types.

Furthermore, researchers found more patients with blood type A and AB have greater rates of lung related injuries from COVID-19. As a conclusion, results suggest that people who are in those two groups have a higher risk of experiencing organ dysfunction or even failure than the blood type O and B groups.

Another result shows those with blood type O or B spend less time in ICU than those with blood type A and AB. Patients with blood type A and AB  had a median ICU stay of 13.5 days, compared with a median ICU stay of nine days among patients with blood Type O or B.

The researchers also found that the patients with blood type A and AB were more likely to require mechanical ventilation, at 84%, than patients with blood Type O or B, at 61%. Overall, this shows that there is an association between a person’s blood type and their risk of requiring mechanical ventilation, in which if patients have blood type A or AB, their risk of requiring mechanical ventilation and prolonged ICU length of stay increased higher than those with blood type O or B.

However, researchers cannot infer that there is a causation, meaning having blood type O or B will not protect people from contracting COVID-19, because these studies are observational studies not experimental studies – only in experimental studies can researchers infer causation. 

According to a different study in the Netherlands, research teams examined half a million people who were tested for COVID-19 from February to June; of the approximately 4,600 people who tested positive for COVID-19, only 38.4 percent have blood type O. This percentage suggests that those with blood type O have a lower risk of contracting the virus.

Other studies in the United States also show similar results that not a lot of people who have blood type O or B tested positive for the virus. A study published in April found that among 1,559 coronavirus patients in New York City, a low percentage of the COVID-19 infected have blood type O. 

However, many scientists noted that there are limitations and possible errors in these studies, which require them to further investigate and learn more about this topic in the future. In addition, while experts generally agreed that the new findings are interesting, they cautioned that the results are correlational—not causational since the studies are observational; researchers didn’t experiment on the subjects or patients; they only observed data from the past.

Roy Silverstein, chair of medicine at the Medical College of Wisconsin, called the new studies’ findings “interesting cocktail party conversation,” and he added that, with further study, they “could lead to new approaches for prevention or therapy.”

However, he said, “at the present time, there is no reason to think that if you have type O blood, you’re protected from COVID-19.”

People should still be cautious during this pandemic and not take it lightly just because of their blood type since these new findings are new and scientists are still exploring this topic.