One of the things that has been puzzling even the most casual observers of the COVID-19 outbreak is why some people and some parts of the world are so much more affected than others?
Update June 11, 2020: Michigan coronavirus (COVID-19) cases up to 59,496; Death toll now at 5,738
When parts of the world like Italy were being ravaged by coronavirus, people wondered why? Was it that it had been spreading silently there, was it related to different social customs, or was there something genetically different about the population?
Several months ago a research paper looking at patients in Wuhan and Shenzen, China suggested having type A blood was associated with a higher risk for acquiring COVID-19 than other types and type O blood appeared to have the lowest risk for infection.
This paper remains unpublished and has not gone through peer review. Subsequently, a group of researchers at Columbia University in New York looked at the blood type and severity of disease in over 1,500 patients diagnosed with COVID-19 and they also found a higher proportion of blood type A patients and a lower proportion of patients with type O blood who were coronavirus positive.
They did not however find that blood type had any relationship to the risk of requiring intubation or dying from COVID-19. This paper is also preliminary and currently unpublished, but taken together, both of these papers raise the question of how someones blood type and their genetics could be important.
A preprint study from Germany evaluated the genome of nearly 2,000 patients with COVID-19 respiratory failure from seven hospitals in Italy and Spain. They found variations in a person’s genes at two particular places in the human genome were associated with an increased risk of respiratory failure -- One of those places includes the gene for blood type.
The final newest bit of information suggesting a link between blood type and COVID susceptibility comes from a preliminary release of information by the company 23 And Me. They haven’t formally published any data but say their early analysis similarly found people with type O blood were less likely to have tested positive.