There is already prep, a once a day pill that if taken consistently, is over 95% effective at stopping HIV infection, I've heard some sources say it's 100% effective. While it's not medically considered to be a vaccine, most vaccines for other conditions have a lower effectiveness rate.
There is work being done to turn prep into an injectable chip in the arm, like long term contraceptives, but for HIV prevention.
There is work being done to turn prep into an injectable chip in the arm, like long term contraceptives, but for HIV prevention.