[opprobium]

This injection isn't a vaccine, it's an anti-viral drug being used as pre-exposure prophylaxis. The first approval of this approach was in 2012, but using an oral pill with a short half-life taken daily.

That drug is still in use and also highly effective, the new improvement is to provide the same approach with a longer acting injected drug. One reason there has been great interest in this, despite the already effective oral PREP, is that there are thought to be socio-behavior advantages for cases like women in Africa as in this study. For example: the woman does not have to keep a supply of daily pills that a partner can find. Also possibly improved adherence with no missed doses.

The drug itself is not thought to be more biologically effective than the oral drugs, which are basically already at close to 100% effective assuming the patient actually takes them as scheduled.