[8fingerlouie]

She could have a specific mutation in her DNA that protects against other things, that somehow makes COVID-19 worse.

Like the CCR5-Delta32 mutation makes 10% of Europeans resistant to HIV (https://www.sciencedaily.com/releases/2005/03/050325234239.h...).

There are other mutations that appears to combat virus more effectively, but who's to say that there are not mutations that are beneficial for some disease, but catastrophic for others ?