BEIJING — China has begun testing a new AIDS vaccine on a group of volunteers after they were given physical exams and signed waivers, the government said.

A total of 49 volunteers between the ages of 18 and 50 will be part of the three-stage tests, the official Xinhua News Agency said, citing Chen Jie, director of the disease control agency in southern China’s Guangxi region.

The first stage of testing will last 14 months, Xinhua said. It didn’t say what the stage was meant to test, but said the second would cover the “immune nature and safety of the vaccine.”

Chinese drug regulators approved the tests last November. At that time, state media said the vaccine, already tested on monkeys, was developed by Chinese scientists who have studied the genetics of the AIDS virus since 1996.

The agency didn’t offer further details of the tests or the vaccine.

China says it has 840,000 people infected with the AIDS virus and 80,000 with the full-blown disease. Health experts say the true figures are much higher and warn that China could have 10 million people infected by 2010 unless it takes action.

After years of denying that the disease was a problem, China has become more open about its AIDS epidemic. But AIDS activists are still regularly detained and harassed.