Over 7 million people around the world have been infected by SARS-CoV-2, the novel coronavirus. While the virus has claimed over 420,000 lives globally, close to 4 million people have also fully recovered from it.
More than six months into the pandemic, the scientific community is still puzzled by the behavior of the virus that presents new surprises every time it is probed into. One of its major mysteries includes why SARS-CoV-2 barely touches some while it makes others gravely ill. Some studies may have raw answers.
So far, we have been told by medical experts that that our physical wellbeing and immunity have major roles to play in our ability to fight the virus. Those who are weak and have underlying medical conditions – such as diabetes, heart or lung problems, etc. – are more likely to develop severe symptoms once infected, they said. Then, we saw the very young and very healthy fall severely ill and, in many cases, lose their battles against the disease.
Now, some studies are finding that genetics may also have a key role to play in a person’s ability to stay protected against the virus. One such study is from the genetic-testing giant 23andMe Inc. which found differences in a gene that influences a person’s blood type can affect a person’s susceptibility to Covid-19.
Type ‘O’ blood found to be especially protective against Covid-19
Lunched in April, the 23andMe study sought to use millions of profiles in its DNA database to shed light on the role genetics play in Covid-19. Preliminary information from more than 750,000 participants in the study suggests that the ‘O’ blood type appears to be protective against the virus when compared to all other blood types.
The findings revealed that individuals with ‘O’ blood type are between 9 and18 percent less likely than individuals with other blood types to have tested positive for Covid-19. Among those exposed to the virus – healthcare and other front line workers – 23andMe found that the blood type ‘O’ is similarly protective.
“There have also been some reports of links between Covid-19, blood clotting, and cardiovascular disease,” said Adam Auton, lead researcher on the 23andMe study. “These reports provided some hints about which genes might be relevant.”
Type ‘A’ blood linked to a 50% increase in severity of disease
The findings echo another research that has indicated a link between variations in the ABO gene and Covid-19. The research also found a clear link between a person’s blood type and the severity of their reaction to SARS-CoV-2.
Looking at the genes of more than 1,600 patients in Italy and Spain who experienced respiratory failure, the study found that that having type ‘A’ blood was linked to a 50% increase in the likelihood a patient would require a ventilator.
It’s pertinent to note that an earlier Chinese study turned up similar results regarding a person’s susceptibility to Covid-19.
Too early to draw any definitive conclusions
Although the evidence is compelling, it may still be too early to draw any definitive conclusions about the blood type playing an important role in a person’s susceptibility to SARS-CoV-2.
“It’s early days; even with these sample sizes, it might not be enough to find genetic associations,” Auton said. “We’re not the only group looking at this, and ultimately the scientific community may need to pool their resources to really address questions surrounding the links between genetics and Covid-19.”
Plus, the difference in susceptibility among other blood types was not found to be significant. “Because the differences are quite small, an extremely large sample size is needed to explore differences across groups,” said 23andMe in its blog post that announced the study’s findings.