The last pandemic with a death toll anything like (actually much worse than) COVID-19 is the still-ongoing HIV pandemic. It's entering its 40th year.
https://www.vox.com/2015/12/1/9828348/ronald-reagan-hiv-aids
PEPFAR is also one of the more important things the US has done, i.e. there are something like 20 million people alive today thanks to the program.
AIDS was a huge deal back when there was no treatment for it.
I also realize that probably depends largely on where you live.
Yeah, I think this can largely be explained by the usual tendency to focus on our own backyards. Google says 'nearly 13,000 people with AIDS in the United States die each year', and I assume the rate is similar in other wealthy countries. Even if we assume the full total is causally attributable to AIDS, that's significantly less than the usual toll from flu, which we also tend to treat rather casually (which isn't to say that we should).
There is also pre exposure prophylaxis, which isn't a vaccine but does dramatically reduce the risk.
Between the two, the disease just isn't the problem it used to be -- assuming you can afford it. In poor counties it's still a problem.
And at the end of the day if it can't spread through casual contact then it's impact on wider society will be limited once it's understood.
Beyond that, we learned to treat it extremely effectively, today if someone who is HIV-positive adheres to their antiretroviral therapy they have a normal life expectancy.
HIV gets transmitted by sex, sharing needles or similar. So, no, it's not comparable. It's vastly easier to avoid.
Nonetheless, they've made a lot of progress on treatment since I first began hearing about it in high school.
Both PReP and antivirals are also not easy. You don't just get a shot and not worry about HIV for a few years, you have to take a pill every day as long as you're sexually active, and then treatment antivirals are expensive and need to be used consistently as well. One person slipping up can mean a lot of people catch it. Even assuming you know you have it to begin with, which is often not obvious until you've been a carrier for a while.
Never mind religious groups going around vilifying condoms doesn't help.
It's getting better, but yes it is still considered a global pandemic.
I mean, it's not the same thing as COVID but like COVID it carries with it its own unique challenges and at no point has the world dumped billions of dollars into single-use vaccines for it like we've done with COVID. Its stigma has migrated (or compounded) from a "gay disease" to an "african disease".
Honestly, I really hope that one silver lining out of all this is that an mRNA vaccine for HIV might get some development now. There was some work that way before everything got diverted to COVID and now that tech has proven itself so...
So no, an infection does not require one person to slip up. For an infection to occur requires both persons to slip up.
Getting PReP requires regular HIV tests so it is in fact obvious that you are infected, if you get infected.
Of course this indeed only solves the issue in the developed world that can pay for (and wants to use) this medication but there really is no way around that. People that don’t want or can’t pay for this medication won’t want and be able to pay for a vaccine either.