Phase 1 Safety Study of Two Experimental HIV Vaccines

This study will test whether two experimental HIV vaccines are safe and whether they cause any side effects in healthy adults. It will examine the body s immune response to the vaccines and monitor the social impact, if any, of being in an HIV vaccine study. The experimental vaccines in this study are the VRC-HIVADV027-00-VP (also called the rAd35-EnvA vaccine) and VRC-HIVADV038-00-VP (also called the rAd5-EnvA vaccine). The vaccines are made using an adenovirus (virus that normally causes respiratory infections and colds) that has been modified to contain DNA that codes for HIV proteins. The vaccines cannot cause HIV or adenoviral infections. Healthy normal volunteers between 18 and 50 years of age may be eligible for this 2-part study. Part 1 includes 15 people. Part 2 includes 20 people. Part 1 participants receive only the rAd35-EnvA vaccine. The first five people enrolled receive the lowest study dose of the vaccine. If this dose is safe, then the next five people enrolled receive a higher dose. If this dose is safe, then the last 5 people enrolled receive the highest study dose. Subjects in Part I have about five clinic visits over 24 weeks. Part II of the study starts after all injections in Part 1 are given. Subjects in Part 2 are randomly assigned to one of two vaccination schedules. One group receives the rAd35-EnvA vaccine first, followed 12 weeks later with the rAd5-EnvA vaccine. The other group receives the vaccines in reverse order; that is, first the rAd5-EnvA vaccine, followed 12 weeks later with the rAd35-EnvA vaccine. In this schedule, the first vaccination primes the immune system and then the immune response is boosted 12 weeks later with a different vaccine. Everyone in study Part 2 receives the rAd35-EnvA vaccine at the middle dose tested in Part 1. Subjects in Part 2 have about eight clinic visits over 36 weeks. All vaccinations are given as injections in the upper arm. At each clinic visit, participants are checked for health changes or p