Genetic testing firm 23andMe have discovered that Type-O blood is particularly resistant to SARS-CoV-2, the virus that causes Covid-19. Perhaps most interesting is that Type-O blood is also associated with a 66% reduction in the odds of developing severe malaria compared to the non-O blood types, according to a 2007 study.
This might explain why Hydroxychloroquine and other anti-malarial drugs have shown efficacy in treating COVID-19
Last week, peer reviewed research which analyzed the genes of more than 1,600 coronavirus patients in Italy and Spain who experienced respiratory failure suggested that blood type may play a role in the severity of the disease. The found that patients with Type-A blood were linked to a 50% increase in the likelihood they would require a ventilator. The results were similar to an earlier Chinese study regarding susceptibility to COVID-19.
"There have also been some reports of links between Covid-19, blood clotting, and cardiovascular disease," said lead researcher on the 23andMe study, Adam Auton. "These reports provided some hints about which genes might be relevant."
The 23andMe study, which looked at susceptibility rather than severity of illness, included 10,000 participants who told the company they had Covid-19.
The research found that individuals with type O blood are between 9% and 18% less likely than individuals with other blood types to have tested positive for the virus. However, there was little difference in susceptibility among other blood types, the study found. When the researchers adjusted the data to account for factors like age and pre-existing illnesses, as well as when it restricted the data to only those with high-probability of exposure like health-care workers, the findings were the same. -Bloomberg
Auton say that while the results are promising, larger studies are required.
"It's early days; even with these sample sizes, it might not be enough to find genetic associations," he 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."