Blood type is not associated with a severe worsening of symptoms in people who have tested positive for COVID-19, according to HMS researchers at Massachusetts General Hospital. Although the findings dispel previous reports suggesting that a certain ABO blood type could lead to increased disease severity, they did indicate that symptomatic individuals with blood types B and AB who are Rh+ are more likely to test positive for COVID-19 than people with other blood types. Symptomatic people with blood type O are less likely to test positive.

The COVID-19 pandemic has spurred research to find characteristics that render individuals more susceptible to the virus, as well as risk factors that intensify its severity and progression. Some have suggested there may be a link between the disease and blood type.

The researchers drew upon the Mass General Brigham Research Patient Data Registry to assemble a study population of 1,289 symptomatic adult patients whose blood type had been recorded and who had tested positive for COVID-19.

The retrospective review showed no significant connection between blood type and worsening of the disease or blood type and the need for hospitalization, positioning requirements for patients during intubation, or any inflammatory markers.

The findings, say the researchers, need to be further explored to determine whether there is something inherent in blood types B,  AB, and O that potentially induces risk or confers protection in individuals.

Latz CA et al., Annals of Hematology, July 2020

Image: Colorized scanning electron micrograph of an apoptotic cell (purple) heavily infected with SARS-CoV-2 virus particles (yellow), isolated from a patient sample/NIAID