AMBIKA AHUJANONGTAPAN, Thailand (AP) ¿ Nearly 16,000 Thais ignored the false rumors that they were being infected by the AIDS virus, and overcame their fears of becoming social outcasts to participate in the first HIV vaccine trials to show positive results. Many of the volunteers ¿ an eclectic mix of housewives, fishermen, factory workers, laborers and prostitutes ¿ had seen firsthand how the disease ravaged this region of plantations and industrial estates in southeast Thailand, part of the epidemic that kills millions worldwide each year. "In the '80s, the coffin business was booming around here. It was one family after another," said Tanad Yomaha, a volunteer whose sister and brother-in-law died of AIDS. "The temple here had at least one cremation ceremony every night and people were in perpetual mourning." Their dedication ¿ 90 percent of the volunteers stuck with the trial for more than six years ¿ paid off when American and Thai authorities announced Thursday that the experimental vaccine had been found in some measure to prevent infection with the AIDS virus, an unexpected result that many scientists thought would never be possible.