Another study has provided further evidence of the link between blood type and Covid-19. Hot on the heels of research suggesting blood type A may make you more vulnerable to the virus, findings from 23andMe’s huge Covid study appears to show those with blood type O are at lower risk of catching it.
Biotech giant 23andMe released preliminary data from its four-month genetic study of Covid-19 back in June, which suggested people with blood type O were less likely than any other blood type to test positive for Covid-19. Now its findings have been published in a pre-print paper revealing more data on the role of the ABO blood group and susceptibility and severity of Covid-19 cases.
The paper has been shared early in the spirit of making all Covid-related research widely available to other researchers around the world and aid the efforts of finding a vaccine. Although the results are yet to be peer-reviewed, it’s not the first time such a link has been found.
Based on the genetic analysis of over 1 million participants (the preliminary findings released in June looked at 750,000) and a more diverse dataset, 23andMe scientists not only found a strong association between blood type and susceptibility but also the severity of the disease, as well as replicating previous non-genetic findings that Black and Latin populations are disproportionately affected by the virus.
The June results showed that of the 750,000 participants – including 10,000 outside of 23andMe that had been hospitalized with Covid-19 – those with blood type O were 9-18 percent less likely to test positive than other blood types. Looking only at those with a high probability of exposure – healthcare and other frontline workers – that rose to 13-26 percent.
This may be due to the presence of certain antibodies in type O blood that help fight off the virus better. Type A blood has anti-B antibodies in the plasma, and type B has anti-A antibodies. Type O blood has both anti-A and anti-B antibodies. Previous research reported that anti-A bodies were able to inhibit, or even block, the virus binding to the host cell.
Other studies on the link between Covid-19 and blood type have suggested other factors may be at play to explain the apparent decreased risk of blood type O. One study found that those with type O blood were more likely underrepresented in studies, and analyzing antibodies in blood groups found no significant difference compared to others.
However, a meta-analysis of studies on the subject reviewed the findings so far and found the evidence did strongly point to blood type A being more susceptible to Covid-19 and type O less at risk of infection. It didn’t find a correlation between blood type and severity or likelihood of death related to the virus.
The study also found that Blacks and Latinos are more likely to be affected by Covid-19 compared to whites. 23andMe's data showed that African Americans who tested positive for Covid-19 were almost twice as likely as whites to be hospitalized, and when adjusted for sex, income, and underlying health conditions were still 80 percent more likely to be hospitalized. Latinos had a slightly higher risk of hospitalization than whites.
"In other words, race and ethnicity still stand out as a significant risk factor for infection with COVID-19 as well as for the most severe symptoms that require hospitalization," Janie F. Shelton, Senior Scientist at 23andMe, wrote in a statement.