 There have been about 2,800 reported cases since 1984, but independent estimates put the number of cases closer to 12,000.The majority (70–75%) of carriers are male, 25–39, and the predominant mode of transmission is through sexual intercourse.Although the national incidence rate remains relatively low, an independent HIV surveillance study conducted in 2010 by Dr. Louie Mar Gangcuangco and colleagues from the University of the Philippines-Philippine General Hospital showed that out of 406 men having sex with men tested for HIV in Metro Manila, HIV prevalence was at 11.8% (95% confidence interval