An experimental HIV vaccine was safe and triggered strong immune responses in healthy adults and in monkeys, researchers report. They say it also protected two-thirds of monkeys against an HIV-like virus. Though results of animal studies are not always the same in humans, researchers are encouraged by this early-stage study, which included nearly 400 healthy people. For their next step, they are launching a new vaccine trial that will include 2,600 women in southern Africa who are at risk of HIV infection. The experimental HIV-1 vaccine is one of five that have progressed to tests of effectiveness in humans. While previous experimental HIV-1 vaccines have usually been limited to specific regions of the world, this vaccine combines different HIV viruses. The aim is to trigger immune responses against a wide variety of HIV strains, according to authors of the study published Friday in The Lancet medical journal. About 37 million people worldwide have HIV/AIDS, and there are 1.8 million new cases a year.