Two studies recommend people who have blood type O may be slightly affected by Covid-19 infection and have a smaller risk of becoming grievously ill; Specialists insisted more research is needed. The study gives more confirmation that blood type may affect a person’s sensitiveness to disease and their risk of having a severe stage of the illness. However, the reasons for this association need more analysis to say if it has positive effects on patients.

Research from Denmark noticed that among 7,422 people who were tested positive for Covid-19, only 38.4% have blood type O — even though among a group of 2.2 million people who were not tested, that blood type made up 41.7% of the group. When matched with another group, 44.4% of group A tested positive, while in the other broader Danish population in that blood type makes up 42.4%. Furthermore, Canadian experts revealed that of all 95 cases severely ill with Covid-19, a proportion with type A or AB — 84% — required to use mechanical ventilation when compared to patients with blood type O or B, which was 61%. The Canadian study also identified those with blood type A or AB stayed longer in the Intensive Care Unit (ICU), compared with people with blood type O or B.