<qa>  What is the usual antibiotic treatment for?All patients will be treated with the usual antibiotic treatment for any sexually transmitted infections that are diagnosed during the study. In addition, half will receive acyclovir for 8 weeks , whilst the other half will receive a placebo for 8 weeks. The study medication will reverse in the second 8 weeks of the study. The patients will attend the clinic 3 times per week during the first and the last 8 weeks of the study and once every week during the washout period in the middle of the study - for a total of 18 weeks per participant. At each visit genital and oral samples will be collected. A blood sample will also be collected. For women participants, pregnancy test will be performed. The clinic will provide both pre- and post-HIV test counseling. 