Hi sir. One doctor told me hiv ofter many years become positive. It is true. Only single unprotected vaginal sex exposure no further exposure what is the hiv windowperiod. Some say Dr. 3 months Some say Dr. 6 months Some say Dr. 1 year. Some say many years. What is the truth. 17 months post exposure hiv 4th generation alere combo negative. It is conclusive. In future can change my result.