Great question, @audreydutton! The short answer is we still don’t have this all worked out and are not completely sure. Now, here’s the longer answer. Men throughout the world do seem to have higher mortality rates with COVID, and although we don’t have many studies yet, it does https://twitter.com/audreydutton/status/1335325522574753793

appear that there is a slight female predominance in long-haulers. In other words, women are more likely than men to survive COVID, but then may be more likely to have long-term effects. While we do think that female hormones may play a role, we think it is more likely tied to

our genetic differences. In animal studies estrogens did seem to have a protective effect. There are studies giving female hormones to men, but I have not seen the results of those studies yet. Interestingly, estrogen does seem to down-regulate (decrease) ACE-2 receptors, so that

may be one factor in why women do better. But the X-chromosome does affect the immune response and since women have 2 x-chromosomes, but men only 1, it is possible that this is an important factor. A protein that is important for viral sensing (identifying that the body is being

attacked by the SARS-COV-2 virus and then signaling immune cells to respond is coded for by a gene on the X-chromosome. The X-chromosome also encodes for other things that are important for the innate (the 1st response that is general and non-specific) and adaptive (the second

phase that is specific and mediated by antibodies and T-cells) immune responses. Further, the X-chromosome genes impact cytokine production, so women may have a more vigorous immune response that might save them from dying, but potentially, this greater immune response sets them

up for long-term effects, which we suspect may be immune-mediated, but we just don’t know yet.