It has made things vastly better for the people who are already infected with HIV. Two-thirds of the people with HIV in the world live in sub-Saharan Africa. Not that long ago, we just filed treatment for those people in the "too hard for now" basket. It was going to be too expensive, the health systems weren't up to it, blah, blah, blah. The extraordinary generosity of the US taxpayer has changed all of that.  Now, a third of people who need treatment in Africa are getting it, and the numbers are growing fast. BUT (there's always a but...) some of the restrictions imposed by Congress have made it really hard to do good prevention, which is far cheaper. So we're in this ridiculous position where we won't spend a few cents on clean needles to help drug injectors avoid HIV infection, but once they do get infected we're happy to spend thousands of dollars on life-saving drugs for them.

How does the Christian Right in the US affect prostitution in Asia?

The Christian Right takes an abolitionist approach. They think the only way to deal with the sex trade is to eradicate it. That has led to what we call the anti-prostitution pledge. Anyone who wants to get US funding for their efforts against HIV has to sign this pledge, which basically says that you won't recognize women's right to sell sex (or men's, or transgenders', either, for that matter), and that you won't work in any way that increases health and safety in the sex industry. It applies even if you're using US money only to deal with AIDS orphans or to provide HIV treatment for sick mothers. In other words, if you want any US money for anything, you can't even use your own money to work constructively to increase health and safety for sex workers. (The government of Brazil turned down $40 million in US funding rather than sign the pledge. Good for them, is what I say!) In Asia, most sex workers choose to sell sex because it is decent money for not very much work, with flexible hours. The turnover is quite high -- many go on to do other jobs after they've built up a bit of capital. It seems to me that it's a good idea to provide HIV prevention services to make sure that they're not infected with a fatal disease by the time they move on, but the Christian Right appears to disagree.

In the United States, who's most at risk? Should everyone be worried, or are there populations of people for whom the AIDS risk is really, really low?

You're at risk for HIV if you share a needle or have unprotected sex with someone who's likely to be infected. Since most HIV infection in the United States is concentrated among people who inject drugs and among gay men, that's where you're most likely to encounter an infected partner. HIV rates are high among people in jail, too, so it's not a good idea to have unprotected sex in jail or with someone who has been inside. Among young heterosexuals, there's not all that much HIV infection around. There are lots of other things to worry about: herpes, HPV and all the "classic" sexually transmitted infections--chlamydia, gonorrhea and the rest--but you're frankly at pretty low risk for HIV unless you're shooting up drugs, cruising the gay scene, in jail, or having sex with someone who does one of those things.

In the fight against AIDS worldwide, what would you say are the three most important things that need to happen/changes that need to take place?
 
We need to make sterile needles available to everyone who injects drugs, and hugely increase methadone and other treatment programs to help people stop injecting. We need to drop the pretense that everyone who has sex is at risk for HIV, and focus our prevention efforts on people who really are at risk. In most of the world that includes gay men and people who sell and buy sex. We need to recognize that people get high and have sex because it's fun and addictive, and take that into account in our prevention efforts. As long as we go on pretending that people are at risk for HIV only because they are poor and ignorant, we'll never get anywhere.

Why should people in the States buy your book?

Mainly because it is a cracking good read about sex and drugs. It will introduce you to all sorts of interesting characters, from transgender sex workers to nuns who work in brothels, all of whom have interesting stories to tell. (After reading the book, one journalist asked me what it was like to live inside a Lou Reed song!) But also because US taxpayers will invest $65 billion in HIV prevention and care in poor countries between 2003 and 2013. They should know how that money is being spent, and how it could be spent better. AIDS is deadly, but books about it don't have to be.