As far as I'm aware you can't get any cover for it. Strange situation whereby it is preventable. But so is diabetes, many cancers and heart disease yet these conditions are usually covered by policies.
Almost every insurance policy and not just pilot centric ones will have exclusions pertaining to Hiv or other GUM related issues.
However HIV is not the showstopper it once was. It's still very serious. You can't get an initial class 1 however you can retain it with a lot of (expensive) investigations by specialists, close involvement of the CAA and constant monitoring. I think you'll also get an OML restriction.
Do remember though that although it's *technically* possible to carry on flying whist HIV+, I'm not actually aware of it actually being achieved. I'm not saying it's not possible, but what I am saying is that I've not heard of anyone actually doing this. Has anyone else
Best avoid. PrEP is not compatible with flying neither unfortunately.