A study by genetic-testing major 23andMe Inc. has found more evidence on how differences in ABO gene, which determines a person's blood group, regulates susceptibility to novel coronavirus. Preliminary data from the study indicates that O blood type appears to be protective against the virus when compared to all other blood types.
"Individuals with O blood type are between 9-18 per cent less likely than individuals with other blood types to have tested positive for COVID-19, according to the data. There appeared to be little differences in susceptibility among the other blood types. These findings hold when adjusted for age, sex, body mass index, ethnicity, and co-morbidities," 23andMe said in a blog post.
When looking at only exposed individuals, those with O blood group were 13-26 per cent less likely to test positive for coronavirus, the study found. Among those exposed to the virus, including healthcare and other front line workers, 23andMe found that blood type O is similarly protective, but the proportion of cases within strata is higher, the study said.
23andMe also found that differences in rhesus factor (blood type + or -) did not affect whether the blood type was protective against coronavirus, nor was this a factor in susceptibility or severity in cases.
The study is still underway, with 23andMe scientists yet to finish looking at what the genetic data indicate. So far, 750,000 participants have been studied, with plans to include 10,000 more particpants outside of 23andMe who have been hospitalised and diagnosed with COVID-19.
Earlier this month, researchers had identified proteins in the blood of COVID-19 patients which are linked to the disease severity. This development is expected to lead to markers that provide information on the progression of their illness.
In March, results of a preliminary study from China had stated that people with Type-A blood are more vulnerable to coronavirus. The same study had concluded that people with Type-O blood could be more resistant to coronavirus.