Blood Type Doesn't Grant COVID Immunity

Blood types are determined by the presence or absence of certain substances (antigens) that can trigger an immune response if they are foreign to the body according to the American Red Cross. The four most common blood types are: A+, A-,  B+, B-,  O+, O-,  AB+, and AB-. Misbar discovered that several studies have been conducted to determine if blood type makes a difference when it comes to COVID-19. 

According to Bioethics.com, blood type A was associated with a greater risk of severe COVID-19 in one recent study and a higher risk of contracting the disease in another. The findings were based on health record data on close to 5,000 patients hospitalized or with an emergency department visit who received a positive COVID-19 test. Type A blood was associated with the increased risk of death among COVID-19 patients compared to type O and type B. 

In another study, research showed patients with type O and Rh- blood groups may have a lower risk of severe COVID-19 infection and illness, according to Infectious Disease Advisor. Investigators conducted a study of 225,556 patients who had their ABO blood group assessed between January 2007 and December 2019, and subsequently tested for COVID-19 between January 15 and June 30, 2020. The O- blood group had a 2.1 percent chance of getting COVID-19 infection, the lowest unadjusted probability of all blood groups. Comparatively, the highest unadjusted probability of COVID-19 infection was in the B+ blood group. 

Another small study also showed a trend in blood types related to COVID-19. A higher proportion of COVID-19 patients with blood group A or AB required mechanical ventilation and had a longer ICU stay compared with patients with blood group O or B.

While there does appear to be a connection between blood type and disease severity when it comes to COVID-19, it is inaccurate to say that people with certain blood types are immune. According to Anahita Dua of Massachusetts General Hospital, who has studied blood types and COVID-19: “No one is immune to COVID-19.” Sean Stowell of Brigham and Women's Hospital reiterated: "Everyone, regardless of blood type, is susceptible to this disease and can die from this disease."