Early in the pandemic doctors began tracking the association between COVID-19 disease severity and a patient’s blood type. Researchers have validated those early observations, finding that several blood proteins are Causal linked to an increased risk of hospitalization and death from COVID-19.The earliest observational studies to come out of Wuhan in 2020 pointed to a correlation between a person’s blood type and their risk of serious illness from a SARS-CoV-2 infection.
The general observation was that those with type A blood seemed to be at a much higher risk of hospitalization and death than those with type O blood. A new study was published in the journal PLOS Genetics.The study has offered insight to date into the Causal relationship between blood type and COVID-19 severity. The research used an analytical method called Mendelian randomization to assess the relationship between the gene variants that govern levels of blood proteins and COVID-19 disease outcomes.
The researchers screened over 3,000 blood proteins, and COVID-19 severity was determined by either hospitalization or death. One of the key findings was a Causal association between COVID-19 severity and an enzyme known as ABO, which defines a person’s blood type. Christopher Hübel from King’s College London said the new research did not interrogate the relationship between specific blood types and COVID-19 severity. However, he does point out the ABO findings do validate prior observational studies linking type A blood with an increased COVID-19 risk.