There’s a piece doing the rounds on various media wires claiming that the Gates-funded Avahan program prevented a large number of HIV transmissions in India, reducing the prevalence of the virus by as much as 13% in Karnataka, the state where it was most successful. The first thing to note about this is that that’s 13%, not 13 percentage points. The prevalence of HIV in Karnataka is only 0.5%, so that’s a drop of 0.065%. So this sounds a whole lot bigger than it really is.
Beyond the framing of the results, I’m also dubious that they’ve really shown this effect. It looks like what the study does is to regress new HIV cases on Avahan spending at the clinic level. That’s not a great way of determining the impact of the program. I would look at the article itself to confirm this but, infuriatingly, it is still gated at TheLancet.com so all that can be seen is the abstract. This is especially aggravating because 1) my university has a subscription to The Lancet and I can generally see their entire archive and 2) most of the articles on the site are ungated for everyone. Indeed, I just read an “online first” article from there the other day. If I were a cynic, and I am, I would point out that this gives them a nice grace period to tout their success without being subject to informed criticism.
Even if these results are real, the cost per averted infection is $2500, which seems really high to me. Figures from Africa, where purchasing power is broadly similar, are around $300 per infection prevented by treating other STIs or using nevirapine to prevent mother-to-child transmission.