Blood type O and covid:
2.1. Data supporting blood type correlation with severity of illness
Ray et al [21] published the largest study to date in Canada, investigating the association of blood type with COVID-19. This population-based cohort study from Ontario included a total of 225,556 patients who underwent polymerase chain reaction testing for SARS-CoV-2.
Among these, 7,071 (3.1%) tested positive for the virus. Adjusted relative risks (ARRs) were calculated after adjusting for patient demographic data and medical comorbidities.
The authors found that individuals with type O blood were less likely to contract SARS-CoV-2 compared with non–type O blood groups (ARR = 0.88; 95% confidence interval [CI], 0.84–0.92). Rhesus (Rh)-negative individuals were also less likely to be diagnosed with SARS-CoV-2 (ARR = 0.79; 95% CI, 0.73–0.85).
Interestingly, individuals with O-negative blood type were further protected against viral infection (ARR = 0.74; 95% CI, 0.66–0.83). Type O individuals were at decreased risk compared to non–type O individuals with regard to secondary outcomes, such as severe illness and death (ARR = 0.87; 95% CI, 0.78–0.97). Rh-negative individuals were also at lower risk of severe illness and mortality compared to Rh-positive patients (ARR = 0.82; 95% CI, 0.68–0.96).
Taken together, the authors concluded that type O and Rh-negative blood groups may be protective against SARS-CoV-2 infection and illness.
One theory that I hear, which strikes me as somewhat true is that humans with O- blood are a slightly different species than other humans. I’m speaking metaphorically on that, to try and make my point understandable.
Because the Rh (-) is not naturally found in the human race and there is no confirmation as to how it became part of the human race. So, those who are Rh (-) are a slightly different species of human than other humans.
It may not be so much as a superior immune system at work as simply that they are slightly less compatible with virus that can normally affect the human race.