San Diego ? Aggressive, early anti-viral therapy might provide a way to derail the spread of AIDS, a battle where a successful vaccine remains elusive.

Called “test-and-treat,” the goal is to catch new AIDS cases early and administer therapy to reduce the amount of virus in patients’ systems in an effort to prevent them from spreading the illness.

While anti-retroviral therapy has increased in the last five years it has often been given too late in the course of infection. By the time people start therapy they have infected most of those that they would have infected anyway, Brian Williams of the South African Centre for Epidemiological Modelling and Analysis told the annual meeting on the American Association for the Advancement of Science on Saturday.

And the National Institutes of Health is now looking at testing the strategy in the United States.

Some 40 million people are infected with HIV/AIDS worldwide and the plague continues to spread, researchers said.

“The problem is we are using drugs to save lives, we’re not using them to prevent infection,” Williams said. Much of the spread of the infection is by people who are not yet aware they have the virus.