Corona vs HIV Viruses

Corona and influenza viruses are single-stranded RNA viruses. Once they get into your cells they start replicating, which your immune system is very good at recognizing and killing. That’s why these kinds of viruses infect once and most of the time they are done.

Herpes on the other hand is a double-stranded DNA virus. It can get into your cells and just sit there not replicating, so it is hard for your immune system to detect it. It will become active and replicate periodically, but then it infects other cells where it will just sit dormant again. So your immune system is playing whack-a-mole, which isn't very effective.

In the case of HIV, it is a retrovirus, so it actually integrates into your cells’ own DNA. You can't get rid of it without killing the host cell, and the cells it primarily infects are T-cells, which are immune cells that are generally tasked with antiviral immunity and it kills the very cells responsible for killing it. It can also hide in other cells that create a reservoir for it to become infectious again, which makes it even more difficult to treat.