Recent studies suggest there may be a link between a person’s blood type and their risk of becoming infected with the coronavirus.
A June 17 study published in the New England Journal of Medicine focused on potential genetic factors in severe cases of COVID-19 with respiratory failure. The study involved nearly 2,000 patients with COVID-19 at seven hospitals located in Spain and Italy. Researchers observed that type O blood was associated with slightly more protection from the virus, while those with type A blood may be more vulnerable to the disease.
According to the study’s authors: “Our genetic data confirm that blood group O is associated with a risk of acquiring COVID-19 that was lower than that in non-O blood groups, whereas blood group A was associated with a higher risk than non-A blood groups.”
Dean Winslow, MD, an infectious disease physician at Stanford Health Care, tells Yahoo Life that the study results are “very interesting,” adding: “I think the association they came up with is real. They found that patients with blood type O seem to be slightly protected from infections — period. And folks with blood type A were basically not protected from infection at all; they had a trend that was statistically significant of requiring oxygen supplementation or mechanical ventilation.”
This isn’t the first study to find correlations between blood types and the risk of COVID-19. Another study, conducted by Chinese researchers in March, found that “blood group A was associated with a higher risk for acquiring COVID-19 compared with non-A blood groups, whereas blood group O was associated with a lower risk for the infection compared with non-O blood groups,” according to the study’s authors.
Iahn Gonsenhauser, MD, chief quality and patient safety officer at Ohio State University Wexner Medical Center, tells Yahoo Life that, while there are a handful of studies that have found type O blood appears to correlate with lower risk and better outcomes for COVID-19 and type A blood with a higher risk and poorer outcomes, “it’s really important to understand that these are observational studies. They can show us a correlation, but they can’t show us a cause. They’re showing us there's a pattern and they've identified a pattern and not whether they are [the cause] or are incidental.”
However, Gonsenhauser notes that the study is a “reasonable observation,” adding: “There are other related scientific findings and evidence that would suggest that this relationship may, in fact, be causal.”
Winslow says blood type might be “just one more factor” that may explain why certain individuals respond differently to this virus.
But this doesn’t mean that people with type O blood should be less worried about the coronavirus in general. "They have a decreased risk to get infected and to develop severe disease," one of the study’s co-authors, Andre Franke, a professor of molecular medicine at the University of Kiel in Germany, told NBC News. "However, this is only a relative risk reduction, i.e. there is no full protection. Among our patients who died there were also many with blood group O." (Yahoo Life reached out to Franke, who was unavailable for comment.)
Adds Gonsenhauser: “These findings should not change anybody’s behavior. We still need to be social distancing and wearing masks. Those are our best tools.”
For the latest coronavirus news and updates, follow along at https://news.yahoo.com/coronavirus. According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC’s and WHO’s resource guides.
Read more from Yahoo Life:
Want daily wellness, lifestyle and parenting news delivered to your inbox? Sign up here for Yahoo Life’s newsletter.