They don't ask people to live their lives any differently than they would, nor do they expose anyone to HIV on purpose; they just track them assuming that x% of people get HIV in any given year. So they compare what X is for people who got the shot, vs those who did not.
As I skim TFA, they say nobody who got the shot ended up getting HIV, which would be statistical anomaly for the population they tested.
Twice a year, but yes. That's a huge benefit -- not only is it easier for patients to stay on the treatment, but it's likely to be a lot cheaper as well.
I wonder how much variation there might be in terms of margin of error. Like, how close do they have to get to keeping people on a rigid 6-month schedule? Would 7 be fine? For what percentage of people? I'm assuming they have reason to believe once a year isn't enough, so that's an upper bound, but what's the lower one?
> I wonder how much variation there might be in terms of margin of error.
Probably quite a bit. The trial used the same dose of lenacapavir as what's used for maintenance in HIV patients; it's quite possible that less is needed to prevent infection in a healthy patient. Unfortunately, there's really no safe/ethical way for them to test lower doses.
the short answer is no one knows (yet). if/once it gets approval, there likely would be a followup study on how much you can stretch the timing (possibly with dosage variation)
As I skim TFA, they say nobody who got the shot ended up getting HIV, which would be statistical anomaly for the population they tested.