Blood Type May Play a Role in Covid-19 Susceptibility
A 23andMe study of more than 750,000 customers offers new insights
In April, DNA testing firm 23andMe began combing its vast consumer database to uncover genetic links to Covid-19.
Now, preliminary results from the company’s study, which looked at genetic profiles of more than 750,000 customers, suggest that people with blood type O may be more protected from getting the disease than those with other blood types. The company zeroed in on a variant in the ABO gene — the gene that determines your blood type — that seemed to be associated with a lower risk of infection.
23andMe found that compared to individuals with other blood types, those with type O were between 9% to 18% less likely to have tested positive for Covid-19. Among health care and other frontline workers, who are more likely to be exposed to the virus, type O blood was similarly protective.
The results are still preliminary, and a major caveat is that the study relied on self-reported Covid-19 cases and hospitalizations from customers.
While not definitive, the results add to mounting evidence that the gene that determines blood type may be important in Covid-19. For instance, researchers in China also found that those with type O blood were at less risk of infection. People with type A blood seemed to be more likely to get infected and more likely to die from complications of Covid-19. The preliminary findings were posted to a preprint server and have not yet been peer-reviewed.
Another preprint by researchers in Italy and Spain found that people with Covid-19 with type A blood were 50% more likely to need oxygen or go on a ventilator. That study looked at the genes of more than 1,600 people with Covid-19.
23andMe is now trying to find out whether genes can explain why some people with Covid-19 have more severe symptoms than others. It’s hoping to recruit 10,000 people who have been diagnosed with Covid-19, including people who have been hospitalized.
Genetics company Ancestry.com, 23andMe’s competitor, is also mining the genomes of its customers for clues about disease severity and susceptibility. For both Ancestry and 23andMe’s studies, customers who have opted into sharing their DNA for research are asked to fill out a survey.
Another effort, called the Covid-19 Host Genetics Initiative, involves researchers from academic institutions across dozens of countries.
We already know that age and underlying disease are risk factors for Covid-19. But there are still some healthy and younger adults that are hospitalized and die from the infection. In the future, the study results from 23andMe, Ancestry, and other large-scale genetics studies could help identify those more likely to get a severe infection by finding important risk factors for Covid-19.