Safety and Effectiveness of Administering an HIV Vaccine in the Groin Versus the Arm

The purpose of this study is to determine the safety of and immune system response to the ALVAC-HIV (vCP205) vaccine when it is injected either into the groin area or into the arm. The goal is to determine if injecting the vaccine into the groin area produces a better immune response in the lining of the rectum.

HIV is most commonly transmitted via a mucosal surface. The mucosal lining is a potential site of both humoral and cellular protection through the activity of B lymphocytes, activated memory T lymphocytes, secretory IgA, and antigen presenting cells. In addition to systemic immunity, a preventive HIV vaccine should induce immune responses at the mucosal surfaces that are portals of HIV entry into the body. Targeted lymph node immunization involves vaccine injection into the subcutaneous tissue near a lymph node. This strategy has proven effective in the simian immunodeficiency virus (SIV)/rhesus macaque model. The iliac and inguinal lymph nodes in the groin are the primary draining lymph nodes of the genitourinary and rectal tracts. This study will evaluate and compare the safety and immunogenicity of ALVAC-HIV (vCP205) when administered subcutaneously in the groin and intramuscularly in the deltoid region. ALVAC-HIV (vCP205) is a canarypox virus vector vaccine expressing portions of the gp120, Gag, and Pol genes. Participants in this study will be randomly assigned to receive vaccine or placebo injections in the groin area or the upper arm. All participants will have three baseline visits for blood tests and sigmoidoscopies to measure baseline immune functions. After these visits, participants will receive weekly injections for 4 weeks. Groin injections will be given subcutaneously (under the skin) and upper arm injections will be given intramuscularly (into the muscle). Participants will have follow-up visits 5 and 11 months after the last immunization. Participants will have blood draws and sigmoidoscopies and will receive HIV risk reduction counseling throughout the study. Total length of participation will be approximately 14 months. Participants may continue to contact the study for HIV testing and study-related concerns for 1 year after study participation.