The second phase of a human trial for China's potential HIV vaccine started on Tuesday in Beijing.

About 150 volunteers, mostly those with a high risk of contracting HIV, including gay people, took part in the clinical trial.

Shao Yiming, director of the virology and immunology department of the National Center for AIDS/STD Control and Prevention, said at a news conference that the trial will last nearly two years in the Beijing You'an Hospital of the Capital Medical University.