An appropriately cautious assessment:
"Meta-analyses on the pooled data showed that blood group A had a significantly higher risk for COVID-19 compared with non-A blood groups," the researchers write in their paper.
"Whereas blood group O had a significantly lower risk for the infectious disease compared with non-O blood groups."
But the paper also clearly states that although the results were significant, it's not an all-or-nothing result.
As per the study, the normal population in Wuhan has a blood type distribution of 31 percent type A, 24 percent type B, 9 percent type AB, and 34 percent type O.
Those with the virus, by comparison, were distributed as follows: 38 percent type A, 26 percent type B, 10 percent type AB, and 25 percent type O. Similar differences were observed in Shenzhen.
As you can see, the percentages between the normal population and those with the virus have some differences - but it doesn't mean that people with type O blood type are immune; and not everyone who gets the virus is going to be type A. Far from it....
The authors of the blood group paper uploaded to medRxiv aren't sure [what explains the differential rate of symptomatic infections], but they suggest that maybe it has to do with the anti-A antibodies that both type B and type O have.
That's just a hypothesis for now, and until we find out more, don't take it as gospel.
