As per an amendment (dated December 19, 2005), follow-up for this study will be extended. The purpose for this extension is to examine in greater depth the efficacy of the vaccine. Specifically, investigators will be exploring whether there is a persistent immune response in participants who received the vaccine as well as if new or boosted responses to the adenovirus vaccine are persistent. The extended follow-up will last for 2 years with clinic visits every 4 months. During visits blood will be drawn for laboratory tests, including HIV testing. Participants will also be informed of ways to reduce their risk of contracting HIV. Two weeks after each visit, participants will be asked to come to the study site for a short post HIV test counseling visit. There will be a total of 6 visits per year, 3 follow-up visits, and 3 post HIV test counseling visits. There will be no more vaccinations.