In Hong Kong the reported cases of HIV/AIDS are increasing every year and the accumulated cases at the end of June 2008 were 3,822 cases of HIV infection and 966 cases of AIDS. The main mode of transmission is sexual contact. Recently, an increase in infection among MSM is prominent and in 2004 the number of infections among MSM exceeded those of heterosexuals. Among newly-infected cases in 2007, homosexual contacts were 44 per cent while heterosexual contacts were 20. It is reported that nearly 70 per cent of the infections among homosexual contacts happened within Hong Kong. The number of infections among IDUs is increasing and they have come to occupy 10 per cent of all PwA/PwH. As for the age ratio, among infected people those in their twenties and thirties are predominant and of AIDS patients nearly 50 per cent are over 40. According to survey data, the infection rate is about 4 per cent among MSM and less than 0.5 per cent among other subgroups (female sex workers, IDUs, STD patients, prisoners).