COVID-19 disease severity tied to patient’s blood type

March 8, 2022
COVID-19 disease severity tied to patient’s blood type

King’s College London (King’s), UK, researchers have identified several causal links between blood type and risk of serious illness from COVID-19. It was found that those with type A blood were at much higher risk of hospitalisation and death compared to those with type O blood, due to the type of blood proteins they produce.

The researchers screened over 3,000 blood proteins through the Mendelian randomisation analysis method. Mendelian randomisation would assess the relationship between the gene variants that determine levels of blood proteins and COVID-19 disease outcomes, where severity was determined by either hospitalisation and respiratory support or death.

“Causality between exposure and disease can be established because genetic variants inherited from parent to offspring are randomly assigned at conception similar to how a randomised-controlled trial(s) assign people to groups,” explained Dr. Vincent Millischer from the Medical University of Vienna. “In our study the groups are defined by their genetic propensity to different blood protein levels, allowing an assessment of causal direction from high blood protein levels to COVID-19 severity whilst avoiding influence of environmental effects.”

One of six proteins, ABO, was associated with COVID-19 severity; King’s Dr. Christopher Hübel said the ABO findings validate prior observational studies linking type A blood with an increased COVID-19 risk.

“The enzyme helps determine the blood group of an individual and our study has linked it with both risk of hospitalisation and the need of respiratory support or death,” said Dr. Hübel. “Our study does not link precise blood group with risk of severe COVID-19 but since previous research has found that proportion of people who are group A is higher in COVID-19 positive individuals, this suggests that blood group A is more likely candidate for follow-up studies.”

[There are a few risk factors beyond blood type known to play a role in COVID-19 severity, including age and pre-existing illness. The research findings should not alarm those with type A blood.]

The findings have also highlighted novel pathways which could be used as treatment or form preventative therapies for COVID-19. A small fraction of blood proteins screened, known as adhesion molecules, moderate interactions between immune cells and blood vessels – it can become a therapeutic target to prevent sick patients deteriorating in hospital.

Read: New COVID-19 test delivers accurate results in just 4 minutes

Category: Education, Features

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