New Yorker Dr. Seth Berkley heads the International AIDS Vaccine Initiative (IAVI), a $600 million project he set up almost a decade ago. This year IAVI has launched human trials of an HIV vaccine in India, one of eight countries in the program. Berkley talked to TIME's South Asia bureau chief Alex Perry about why a vaccine offers the only permanent solution to AIDS, and why India plays a crucial part in its development.TIME: Is a vaccine possible?BERKLEY: Every indication we have leads us to say that vaccination is going to be possible. If you take weakened HIV and put it into monkeys, you get full protection. And there is a group of people who do produce the right type of antibodies for HIV. The problem is we don't know why. We have the lock, but we do not have the key.TIME: Why do we hear more about treatment drugs than a vaccine?BERKLEY: So far people have demanded treatment. [Their attitude is:] This person is dying, they need drugs. They have focused on giving hope, not on the problem. As a result, we are building a situation that is completely unsustainable. When we started IAVI, the world was spending less than $100 million on vaccine research, compared with billions on treatment drugs. And AIDS spread across the world, to Russia, China and India. The only way to end this epidemic is a vaccine.TIME: You've said vaccines are particularly important to India. Why?BERKLEY: It's one thing to go into a small community and say, We want sex workers to use condoms. But in India you have a billion people, and you want them to have condoms every time they have sex? That's 33 billion condoms a year. When you think about a place like India, you have to think of the magnitude of what that entails, and you have to think about vaccines. I do not see what else India is going to do.TIME: Why is India so key for IAVI?BERKLEY: Almost no government has been involved in a serious effort to produce a vaccine. That's why India is so unique. There is a real accelerated leadership there on this issue. India is at the forefront of all countries in the world on this.TIME: Can India produce a vaccine for AIDS?BERKLEY: India could say, Let's wait for the U.S. to develop a vaccine. But there is no enormous need for a vaccine in the U.S. Plus, most of the vaccines for the U.S. are produced in India. India has innovative medical-research companies and an industry, a whole pattern of economic growth, based around science and technology. We could see a situation where India becomes the world's manufacturer of AIDS vaccines.