At study entry, participants will also undergo a syphilis test. Those who test positive for syphilis will receive same-day treatment at the clinic and be asked to return during Week 1 and 2 to complete treatment for sexually transmitted diseases (STDs) according to local guidelines. STD treatment will not be provided by the study. Those who test negative to both the HIV rapid test and the syphilis test at screening will not participate in any more study visits. Patients who consent to having samples stored for further investigations will also have their samples tested for HSV-2 infection following completion of the study.