EUROPEAN scientists, including Spanish researchers, have observed a direct relationship between blood group and the possibility of developing a serious case of COVID-19.
This recent study, published in Medrxiv, suggests that individuals with blood group A-positive are more likely to develop a severe case of COVID-19.
Blood samples were taken from 1,610 people who needed oxygen or a respirator once they had contracted coronavirus.
Using the DNA from these samples, scientists concluded that people with A-positive blood had a 50% increased chance of needing an oxygen supply or a respirator.
The study used 1,980 patients with COVID-19 respiratory failure at seven European epicentres of the pandemic.
Genome-wide association analysis was conducted on subjects in Madrid, San Sebastian and Barcelona, as well as Milan and Monza in Italy.
After quality control and exclusion of population outliers, 835 patients from Italy, and 775 patients from Spain were included in the final analysis.
The researchers analysed nine million genetic letters in each patient’s genome, as well as 2,205 non-coronavirus blood donors.
The aim, to find locations in the genome, called loci, where an unusually high number of the severely ill patients shared the same variants, compared with those who were not ill.
Two loci turned up. One was the gene that determines blood type.
Andre Franke, a molecular geneticist at the University of Kiel in Germany and a co-author of the new study, said that the locus where the blood-type gene is situated also contains a stretch of DNA that acts as an ‘on-off switch’ for a gene producing a protein that triggers strong immune responses.
The coronavirus triggers an overreaction of the immune system in some people, leading to massive inflammation and lung damage.
It is theoretically possible that genetic variations influence that response.
The study expands on what scientists have already determined, that factors like age and underlying disease put people at extra risk of developing a severe case of COVID-19.
Geneticists hope that a DNA test might help identify patients who will need aggressive treatment.
A study conducted in China months ago also showed that those with blood group A-positive were more likely to develop a severe case of COVID-19.
Those results were published after taking blood samples from 2,000 patients.
*The study has not yet been peer-reviewed, though it reports new medical research, it is yet to be evaluated and should not be used to guide clinical practice.