If you really want to go down a rabbit hole, research the apparent functions of CCR5, effects of d32 homozygous mutants, interplay between immunodeficiency, coinfection, viral evolution... while this seems like a Black Swan, this may be the first of several plagues the likes of which haven't been seen for centuries.

We've been extremely fortunate that this wasn't more lethal, and there's a real and significant danger that before this is over, if proper action isn't taken, it may achieve that status. There's also a very real danger that these compromised super-hosts will serve this function for every infectious disease they happen across, with results unclear.