As the pandemic continues, we see more and more research results. It’s rare that you get so many discoveries being made all at once. But, when a virus is as new and dangerous as COVID-19 is, many studies start at the same time. One of these studies shows that people with different blood types react differently when they are infected.

There are four main types of blood: A, B, AB and O. A report from China said that people with Type O blood were more likely to have a mild reaction to COVID-19 or remain asymptomatic.

A new study, using genetic analysis, was reported by the New England Journal of Medicine that supports the Chinese research. It shows that people with Type A blood are more likely to have a severe reaction to the virus. This new study was peer-reviewed and carefully documented. In fact, people with Type A blood were 50 percent more likely to become seriously ill with COVID-19 than other blood types. And people with Type O blood were 50 percent less likely to become severely ill than any other blood type. The SARS virus, in 2002, also made people with Type O blood less sick.

Speaking about the original research from China, Dr. Parameswar Hari, at the Medical College of Wisconsin, said, “Most of us discounted it because it was a very crude study. Now I believe it. It could be very important.”

Other doctors disagree and call the finds tentative. The study involved doctors from around the world in Demark, Germany, Italy, Spain, the U.S. and other countries and compared the blood types of 2,000 people infected with COVID-19.

The study looked at more than 8.5 million genetic factors in the blood of those 2,000 people versus 1,200 healthy blood donors from the same areas. But, more studies are needed to confirm the link. The NIH has launched new research using 5,000 COVID-19 patients in the U.S. and Canada. Their hope is that it might develop into blood tests that could find who might be the most at risk if infected.

Blood types may be associated with how the immune system reacts. Overreaction of the immune system to the virus is thought to be the leading cause of deaths from COVID-19. Overall, the difference in risk for various blood types is small compared to people’s overall health factors. However, the findings are useful for designing drugs or vaccines against coronavirus because having more knowledge is always a tool.

Most people don’t know their blood type unless they have had surgery or extensive blood work. If you don’t know what blood type you have and would like to know more about your risks for COVID-19, speak to your doctor’s office. They may have it on file.