There was something that came out a while back about a certain blood type that seemed to have milder symptoms, but I don't remember the source.
Found this:
Associations between blood type and COVID-19 infection ...www.nature.com › nature communications › articles
Nov 13, 2020 — found a greater proportion of A and a lower proportion of O blood types among COVID-19 patients, relative to the general populations of Wuhan and Shenzhen5. Similarly, using a meta-analysis of data from Italy and Spain, Ellinghaus et al. found6 a higher risk of COVID-19 among A and a lower risk among O blood types.
And from MIT Technology:
Early evidence: As far back as March, Chinese researchers analyzed blood types in 2,173 infected individuals from Wuhan and Shenzhen and compared those results with surveys of blood types from healthy populations in the same region. They found that 38% of the covid-19 patients had type A blood, compared with just 31% of the healthy people surveyed. By contrast, type O blood seemed to lead to a reduced risk, with 26% of the infected cases versus 34% of healthy people. And type A patients accounted for a larger proportion of covid-related deaths than any other blood type. Another study at Columbia University found similar trends: type A individuals were 34% more likely to test positive for the coronavirus, while those with type O or AB blood had a lower probability of testing positive.
