It also depends on how long it stays asymptomatic (so that a host can go around and infect other people before dying) and how well it spreads from host to host, and probably other factors that I don't know about
HIV is one of the three new programs in this announcement. So yes, that's precisely what they're hoping.
(Pedantry: HIV is the virus that causes the disease AIDS. The goal is to prevent AIDS by vaccinating against HIV. It's unlikely that the vaccine would be able to help patients who already have AIDS.)
It is slightly odd that the headline doesn't feature HIV more prominently, since this is a press release. PR puffery would call for a headline more like "We cured COVID and now we're going to cure Flu and AIDS (and another thing you've never heard of)."
Props for modesty, I guess, but this is a weird instance to suddenly get coy.
The list of things they work working on is too long for a headline. I personally find HIV the least interesting (since I'm at extremely low risk by lifestyle - I'd still get the vaccine it work works, but it isn't a big deal to me). To me the correct headline is "moderna isn't working on vaccines for any of the cancers my family members are currently fighting" I have no doubt that someone else will read the article and respond "you idiot, they work working on X which is the most important things possible" - X of course being different for each personal situation.
HIV has effective prevention through both condom use and pre-exposure prophylactic treatment. The vaccine is a big deal in reducing costs, but, it's not as big a deal as the flu vaccine (or even as big as HPV was).
