A new scientific study, published in the journal Epidemics (Source 1), indicates that the most likely explanation is that Sars-CoV-2 infection behaves much like a blood transfusion.
“Using information from around the world, our latest data model indicates that Sars-CoV-2 infection behaves similarly to a blood transfusion and that infected patients are 2-3 times more likely to transmit the virus to someone for whom they are a compatible blood donor”, commented Dr. Peter Ellis, author of the study and researcher at the School of Biosciences at the University of Kent (Canterbury, United Kingdom), in a press release (Source 2).
“This explains why people with type O have a lower risk of infection. Just as they reject non-group O blood transfusions, they can reject virus particles from a patient with ‘non-O’ blood, thus escaping infection”, he continued. “However, individuals with type O blood are universal donors, who can donate blood to anyone. Likewise, once infected, they are also capable of infecting people of any other blood type. Conversely, those with type A blood are more likely to catch the virus and less likely to pass it on.”, added the researcher.
For Dr. Ellis, these data could also partly explain the differences in the severity of the epidemic around the world : countries with a greater variety of blood groups would thus present natural barriers to the circulation of the virus. However, the scientist does not recommend carrying out a targeted vaccination of the most fragile blood groups or those most likely to transmit the virus.