Elizabeth Pisani is taking unfair heat for arguing that HIV treatment is not the same as prevention:

No-one who has seen friends die because they live in a place where they couldn’t get treatment could possibly be anti-treatment. We should be expanding treatment for its own sake. We don’t need to build computer models based on entirely unrealistic assumptions in order to justify the need for more treatment. We DO, however, need to face the fact that until now, more treatment has been associated with more new infections. So as we expand treatment, we need to expand other forms of effective prevention, too.

Sure. But that "associated with" is a pretty gaping loophole, don't you think? It's not even correlation, let alone causation we're talking about here. And there's a huge amount of noise in this study. Read it carefully.

It does not say that someone with undetectable viral load is just as likely to infect another man as someone with a high viral load. It simply says that in the aggregate the average risk of getting infected in a sample of the general population doesn't seem to have shifted since the early 1990s in another part of the world. None of the members of the study, so far as I can tell, was actually tested for viral load. All this is merely inferred from outside the group being studied, as in:

Rates of HIV testing among gay men in Australia are "very high," the researchers note, while 70 percent of HIV-positive men are receiving treatment with powerful AIDS drugs. And three quarters of these men have no detectable virus in their blood.

Questions: What does "very high" mean? What percentage of Aussie gays are positive? At best we can say that 50 percent or so of HIV-positive aussie gays have zero viral loads. But what percentage of the population as a whole is in this category? Or even in this sample?

What we are more likely seeing, I'd guess, is that the drugs that allow people like me to live long, healthy and productive lives have greatly lowered the sense of danger and risk many other younger man feel about sex without rubbers. And that is completely predictable behavior. When you shift the cost-benefit ratio of anything so drastically, behavior tends to change. There was much much more fear in the early 1990s for totally understandable reasons. Your poz friends were dropping like flies; now all your poz friends have huge muscles. So the rate of tested and untested gay men having unsafe sex may well have gone up dramatically. And this is not surprising.

Say you somehow managed to produce a burger which tasted much better and if you took a pill would not make you fat or add to your cholesterol. What do you think would happen to burger sales? And sex is a lot more irresistible for most young men than burgers. Like Elizabeth, I'm not arguing against treatment. I'd like to find effective ways to thwart human nature so that fewer men get infected. But nothing works better than fear; and the fear has lifted. We have to deal with that.

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