The purpose of this study is to determine whether immunizations with an integrated combination of ALVAC-HIV (vCP1521) boosted by AIDSVAX gp120 B/E prevent HIV infection in healthy Thai volunteers.

A vaccine for the prevention of HIV infection remains an urgent need as part of the efforts to control the HIV pandemic. In this phase III efficacy trial, a 'prime-boost' vaccine strategy is evaluated for prevention of infection and ameliorationn of disease course. ALVAC-HIV (vCP1521) from sanofi pasteur is given as the 'prime' vaccine at months 0, 1, 3 and 6; AIDSVAX gp120 B/E from VaxGen is given as the 'boost' at months 3 and 6. This regimen will be given to 8,000 adult Thai subjects, while another 8,000 will be given placebos in a double-blinded, randomized manner. Following the completion of each subjects immunization phase, he/she will be followed for 3 years with clinic visits every 6 months with HIV testing, pre- and post-test counseling. Subjects who become HIV infected will be counseled, referred to HIV treatment facilities for management according to national guidelines, and offered enrollment in a protocol for extended follow-up.

• Biological: ALVAC-HIV vCP1521 + AIDSVAX
• Biological: ALVAC Placebo + AIDSVAX Placebo

• Nitayaphan S, Pitisuttithum P, Karnasuta C, Eamsila C, de Souza M, Morgan P, Polonis V, Benenson M, VanCott T, Ratto-Kim S, Kim J, Thapinta D, Garner R, Bussaratid V, Singharaj P, el-Habib R, Gurunathan S, Heyward W, Birx D, McNeil J, Brown AE; Thai AIDS Vaccine Evaluation Group. Safety and immunogenicity of an HIV subtype B and E prime-boost vaccine combination in HIV-negative Thai adults. J Infect Dis. 2004 Aug 15;190(4):702-6. Epub 2004 Jul 20.
• Karnasuta C, Paris RM, Cox JH, Nitayaphan S, Pitisuttithum P, Thongcharoen P, Brown AE, Gurunathan S, Tartaglia J, Heyward WL, McNeil JG, Birx DL, de Souza MS; Thai AIDS Vaccine Evaluation Group, Thailand. Antibody-dependent cell-mediated cytotoxic responses in participants enrolled in a phase I/II ALVAC-HIV/AIDSVAX B/E prime-boost HIV-1 vaccine trial in Thailand. Vaccine. 2005 Mar 31;23(19):2522-9.
• Brown AE, Nitayaphan S. Foundations for a Phase III human immunodeficiency virus vaccine trial: A decade of Thai-U.S. Army collaborative research. Mil Med. 2004 Aug;169(8):588-93. Review.

Inclusion Criteria:

• Thai citizen, 18-30 years of age; either gender,
• Available for participation for 3.5 years,
• Able to understand study and give written informed consent, Completed enrollment in associated screening protocol

Exclusion Criteria:

• HIV positive,
• Participant in previous HIV vaccine trial,
• Active TB or other systemic disease; immunodeficiency or chronic use of immune modifying therapy,
• History of anaphylaxis or other serious adverse reactions to vaccines,
• For women, breast feeding or pregnant (or planning to become pregnant during the first 9 months after enrollment)

• Armed Forces Research Institute of Medical Sciences, Thailand
• National Institute of Allergy and Infectious Diseases (NIAID)
• Walter Reed Army Institute of Research (WRAIR)
• sanofi pasteur
• VaxGen
• The EMMES Corporation
• Ministry of Health, Thailand
• Mahidol University
• Royal Thai Army Medical Department
• Tripler Army Medical Center
• Henry M Jackson Foundation