This study will utilize existing (collected after 1 January 2006) and prospectively collected HIV seronegative clinical specimens not used as part of any research protocol. The specimens in this study are discarded anonymous samples from the Voluntary Counseling and Testing (VCT) facilities at the Thai Red Cross Anonymous Clinic in Bangkok, Thailand. The specimens cannot be linked to the tested subjects. The samples will be labeled using the anonymous clinic identification number which is a 7 digit number with the first 2 digits representing the year and the following 5 digits representing the sequence of which the client sought care in that calendar year. Preliminary Study of Early, Primary HIV Infection in a High Risk Cohort.