Men who have sex with men (MSM) are responsible for a growing share of AIDS transmissions, according to the latest report released by Shanghai City Disease Prevention and Control Center on Saturday.

Medical experts said Shanghai plans to give free intervention therapy to MSM group, but few men take it so far.

Since the beginning of the pandemic, nearly 78 million people have contracted HIV. By June 2014, around 13.6 million people living with HIV received antiretroviral therapy, according to Kang Laiyi, medical expert of Shanghai City Disease Prevention and Control Center.

In recent years, AIDS prevention and control work has paid off around the world. From 2001 to 2009, the number of new infections worldwide declined by 25 percent and over the past three years, global new HIV infections fell by 13 percent.

MSM have been recognized worldwide as one of the four groups most vulnerable to HIV infection, along with sex workers, drug users and transgender female.

According to 2014 clinical statistics, 92.2 percent of newly detected cases were caused by sexual transmission, among which heterosexual transmission accounted for 66.4 percent and MSM transmission accounted for 25.8 percent.

"HIV prevalence is increasing rapidly among men who have sex with men (MSM) in Shanghai and potentially associated with the number of sexual partners," said Dr. Lu Hongzhou, the Professor and Co-Director of Shanghai Public Health Clinical Center and Physician-in-Chief of Shanghai Center for AIDS Diagnosis and Treatment.

In Shanghai, 56.1 percent of homosexual men have no regular sex partner. 52.5 percent of them have "one night stand" and 64.3 percent of them paid for sex and 48.4 percent of them have sex with opposite sex.

Lu said that Shanghai has plans to provide homosexual men with free intervention therapy. "For healthy men, taking a pill every day basically ensure them not get infected with HIV, even if they had unprotected sex." But few take it, worrying about the side effect of the medicine.