Some people who catch Covid-19, the disease caused by the novel coronavirus, remain asymptomatic, some develop only mild symptoms but many are hit with severe symptoms resulting in hospitalisation and even death.

The nature of the novel coronavirus and how it affects different people differently has puzzled the scientific community. Researchers in all parts of the world are trying to pinpoint exact reasons for such huge variations in the way the SARS Cov-2 affects a person’s body.

Yes, old age and preexisting health conditions do play a part but that doesn’t explain how some old people with illnesses are not affected by the virus while young people with no diseases become severely ill. There are definitely some unknown factors at play.

A group of scientists in Europe have found a strong statistical connection between genetic variations and the Covid-19 disease. Basically, it means that how the coronavirus will impact you was decided the day you were born.

The European researchers studied DNA samples of 1,610 Covid-19 patients from Italy and Spain who needed an oxygen supply or a ventilator. Each person’s genetic code consists of three billion letters. Researchers involved in the DNA study instead looked at over 8.5 million letters after sequencing the genome of the patients.

They carried out same DNA survey of 2,205 individuals who didn’t have Covid-19. When they matched the genome of Covid-19 patients with those who didn’t have that disease, researchers found two spots, called loci, where an unusually large number of badly hit patients shared same variants.

At one of these spots is located the gene that determines a person’s blood type. People having Type A blood group were found to be more vulnerable than others. “A blood-group-specific analysis showed higher risk for A-positive individuals and a protective effect for blood group O,” the study concludes.

At the same spot is another stretch of DNA which is linked to triggering strong immune responses. We have seen many cases across the world where SARS CoV 2 has triggered overreaction of immune system in many Covid-19 patients causing inflammation and damage to lungs.

The second spot which is home to six genes has even more strong link to the severity of the Covid-19 in a person. It will take further studies to determine how those six genes determine the progression of the disease.

Around 1000 scientists from 46 countries are collaborating ”to generate, share and analyze data to learn the genetic determinants of COVID-19 susceptibility, severity and outcomes”. They are collecting DNA samples from Covid-19 patients and posting it online on a website specifically created for this purpose. Andrea Ganna, a genetic epidemiologist at the University of Helsinki, told The New York Times that the “collected data were beginning to point to a single spot on Chromosome 3 as a potentially important player.”

Dr Jonathan Sebat, a geneticist at the University of California, San Diego, who is running a separate study to see if the two spots really matter in deciding the severity of Covid-19 in people, says ’the geneticists may be able to zero in on exactly which gene in each locus (spot in the genome) affects the disease.”

Blood Group

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