The SMC functions as an arm of the EC to provide a review of the conduct of all HPTN studies. Active HPTN studies are typically reviewed by the SMC within the first four to six months of study implementation and thereafter, approximately every six months including prior to Data and Safety Monitoring Board (DSMB) reviews. The Statistical and Data Management Center (SDMC) Principal Investigator (PI) in collaboration with HPTN Leadership will determine the need for and frequency of SMC reviews for each study.