Thread by @DearPandemic

1/ Q. Is blood type really linked to a higher risk of #COVID19?

Short answer: We don’t know yet.

Long answer: read on 🤓

2/ A study by DNA testing company @23andMe reported that people with blood Type O were up to 18% less likely get infected with #COVID than other blood types and were also less likely to be hospitalized.

3/ The findings appear to align, in general, with results from the few other studies available from China and New York City, and most recently from a study in Europe.

4/ BACKGROUND: Blood type has previously been correlated with susceptibility to disease because the blood type gene is located on a stretch of DNA that regulates inflammation and blood clotting. These processes play a role in severity of #COVID_19.

5/ The stretch of DNA that encodes blood type is also located near the region that encodes the ACE2 protein: the receptor for the SARS-CoV-2 virus.

However, we don't know if the genes for blood type have any bearing on ACE2 receptors in any way.

6/ How strong is the evidence so far? We need to keep a few things in mind:

1. Only one study has been peer-reviewed or published yet.
The #23andMe results came in the form of a blog post and have yet to be formally critiqued by other scientists: blog.23andme.com/23andme-resear…

7/ Secondly, because of the way these studies were designed, we can only conclude that there is a CORRELATION (not causal relationship) between blood type and #coronavirus infection.

8/ Similarly, we don’t have hard evidence that a particular blood type worsens disease severity. In the published study patients with blood type A had a greater odds of respiratory failure. But in the NYC study, there were no differences in intubation nor death across blood types

9/ So does this mean people with type O blood can get a hall pass, while the type A’s remain in detention?

That’s a hard NO! In all studies, people with blood Type O still got infected with COVID19, and not all people with blood type A were infected/developed complications

10/ As per Dr. Charlotte Houldcroft at the @Cambridge_Uni, “each variant found here only increases a person’s risk a little bit, and we have no idea how. It doesn’t allow us to predict who will be a severe case” the-scientist.com/news-opinion/t…

11/ LINKS:

Published European study on blood type and respiratory failure:
nejm.org/doi/full/10.10…

Overview of all studies on blood type and COVID-19:
prevention.com/health/a328241…