A new Danish study has found those with type-O blood are less likely to acquire COVID-19. The study states, “we demonstrate that blood group O is significantly associated with reduced susceptibility to SARS-CoV-2 infection. Additionally, ABO blood groups were not associated with rates of hospitalization or death following infection.” One with COVID-19 and type-O blood had a median hospital stay of 9 days, while one with type-A blood had a median hospital stay of 13.5 days.
Those with type-O blood had a 38 percent chance of contracting COVID-19 while 44 percent with type-A blood had a 44 percent chance. Type O and type A blood types are the overwhelming types in the United States. Meanwhile, Type B blood accounts for 8.5 percent of the U.S. population and type AB blood type accounts for 3.4 percent of the U.S. population.
Of 841,327 people tested for SARS-CoV-2 in Denmark, ABO and RhD they could identify blood groups for 473,654 individuals. ABO and RhD data from 2,204,742 individuals not tested for SARS-CoV-2 were used as a reference, corresponding to ∼38% of the entire Danish population.
As the study found, more research into how blood types interact with COVID-19 is needed. ABO blood group information was only available for 62% of all tested individuals, and it identified only doctors and nurses as health care personnel. It skewed the sex of the tested population, with females accounting for 71% of those who screened negative and 67% of those who screened positive. However, blood groups are independent of sex. However, is the fact that blood group distributions vary among ethnic subgroups with different susceptibility for infection. A higher than an expected contribution of immigrants from nonwestern countries is noted among Danish COVID-19 patients, but a sensitivity analysis showed this is not a major bias and, thus, is unlikely to affect the overall conclusion.