Blood Type Resistant to COVID-19?..."Type O Has Lower Risk of Severe Illness and Death" Study

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[Asia Economy Reporter Hwang Sumi] A study has found that individuals with blood type O have a relatively lower risk of severe COVID-19 or death.

Recently, a joint research team from the UK National Institute for Health Research, the University of Cambridge, and the Medical University of Vienna in Austria published findings in the international journal PLoS Genetics indicating that the protein determining blood type is related to COVID-19.

The research team analyzed over 3,000 types of proteins in the blood to identify proteins correlated with COVID-19. They considered blood protein analysis essential for developing new COVID-19 treatments.

At this time, they applied a "Mendelian randomization study." Mendelian randomization is a genome-based study method that uses the random allocation of gene variants during meiosis to compare groups with many gene variants to those with few. This approach excludes other confounding factors and can prove causal relationships between two factors. For this reason, it is widely used in medical research to establish causality.

Through analyzing 5,504 genomes and over 3,000 proteins, the research team identified six proteins that cause severe COVID-19 or death and eight proteins that protect against severe disease or death.

Among the proteins that cause severe COVID-19 or death was the 'ABO' protein, which determines blood type. The team stated, "Further research is needed to determine which blood type has a higher mortality risk," and added, "We will first investigate blood type A, which has been previously reported to have a strong correlation with COVID-19."

Previously, several studies have examined the correlation between blood type A and COVID-19. A research team from Brigham and Women's Hospital at Harvard Medical School in the United States announced on March 4 last year that blood type A is more susceptible to COVID-19 infection. Their study cited the fact that the receptor-binding domain (RBD) of the COVID-19 virus binds well with blood type A as evidence.

A German research team also reported in June 2020 that among 1,980 severe patients and over 2,000 mild or asymptomatic patients from seven hospitals in Italy and Spain, the probability of severe illness was 50% higher in blood type A individuals.

However, a joint research team including the Intermountain Medical Center in Utah, USA, published results stating that no specific relationship between COVID-19 and blood type was confirmed. They reanalyzed previous studies statistically and conducted new large-scale clinical analyses on COVID-19 infection susceptibility and severity by blood type, leading to this conclusion.

Regarding this, the research team stated, "Blood types other than O have a higher risk of severe COVID-19 or death," and added, "There have been several previous studies indicating that blood type A carries the greatest risk, and we will conduct follow-up research on blood type A as well."

In addition to the ABO protein, five other proteins (GCNT4, CD207, RAB14, C1GALT1C1, FAAH2) were found to have causal relationships with severe COVID-19 or death. Among these, GCNT4 showed the strongest causality.

Conversely, three cell adhesion molecules that mediate interactions between immune cells and blood vessels were found to reduce the risk of severe COVID-19 and death. The research team noted that this finding aligns with previous studies linking COVID-19 to vascular endothelial-related diseases.

Jerome Bryne, a researcher at the UK National Institute for Health Research’s Centre for Mental Health Biomedical Research, said, "We will continue follow-up studies to determine the causal relationships between these proteins and severe COVID-19 or death, as well as potential preventive or therapeutic methods."