Several studies show that blood type may be linked with testing positive, but not with severity or hospitalization. Further research is needed.
Many studies have been conducted to try and find the correlation between blood groups and Covid-19. One research suggests that people with Type A may have a higher risk of catching Covid-19 and developing severe symptoms, while people with Type O blood may have a lower risk. A study published in June 2020, counters some of these early findings. Researchers at Massachusetts General Hospital and Beth Israel Deaconess Hospital published a study that found no evidence that blood type affects whether someone develops severe symptoms from a coronavirus infection. The study points out that blood types are not a predictor of Covid-19 severity in terms of death rate and intubation, nor does it correlate with the hospitalization rates. The study reported that symptomatic patients with Covid-19 and type O blood appeared to test positive at a significantly lower rate than patients who had types B or AB or a positive rhesus (Rh) factor.
Another study published in the New England Journal of Medicine in June 2020, found people with Type A blood had a 45% higher risk of becoming infected than people with other blood types. And people with Type O blood were just 65% as likely to become infected as people with other blood types. They studied more than 1,900 severely ill coronavirus patients in Spain and Italy and compared them to 2,300 people who were not sick.
In an April 2020 study published online on medRxiv- scientists looked at 1,559 people who tested for SARS-CoV-2 at New York-Presbyterian Hospital. Out of 1,559, 682 who tested positive, found that individuals with A blood types (A-positive and A-negative) were 33% more likely to test positive than other blood types. Both O-negative and O-positive blood types were less likely to test positive than other blood groups.
All the above studies show that there might be a connection between Covid-19 and blood type and need more research. But there is no clear evidence to show a relationship between blood type and severity of the illness.
The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19 including symptoms, prevention and available treatment, please refer to the World Health Organisation or your national healthcare authority.