Vaccination with ALVAC and AIDSVAX to prevent HIV-1 infection in Thailand.
BACKGROUND
The development of a safe and effective vaccine against the human immunodeficiency virus type 1 (HIV-1) is critical to pandemic control.


METHODS
In a community-based, randomized, multicenter, double-blind, placebo-controlled efficacy trial, we evaluated four priming injections of a recombinant canarypox vector vaccine (ALVAC-HIV [vCP1521]) plus two booster injections of a recombinant glycoprotein 120 subunit vaccine (AIDSVAX B/E). The vaccine and placebo injections were administered to 16,402 healthy men and women between the ages of 18 and 30 years in Rayong and Chon Buri provinces in Thailand. The volunteers, primarily at heterosexual risk for HIV infection, were monitored for the coprimary end points: HIV-1 infection and early HIV-1 viremia, at the end of the 6-month vaccination series and every 6 months thereafter for 3 years.


RESULTS
In the intention-to-treat analysis involving 16,402 subjects, there was a trend toward the prevention of HIV-1 infection among the vaccine recipients, with a vaccine efficacy of 26.4% (95% confidence interval [CI], -4.0 to 47.9; P=0.08). In the per-protocol analysis involving 12,542 subjects, the vaccine efficacy was 26.2% (95% CI, -13.3 to 51.9; P=0.16). In the modified intention-to-treat analysis involving 16,395 subjects (with the exclusion of 7 subjects who were found to have had HIV-1 infection at baseline), the vaccine efficacy was 31.2% (95% CI, 1.1 to 52.1; P=0.04). Vaccination did not affect the degree of viremia or the CD4+ T-cell count in subjects in whom HIV-1 infection was subsequently diagnosed.


CONCLUSIONS
This ALVAC-HIV and AIDSVAX B/E vaccine regimen may reduce the risk of HIV infection in a community-based population with largely heterosexual risk. Vaccination did not affect the viral load or CD4+ count in subjects with HIV infection. Although the results show only a modest benefit, they offer insight for future research. (ClinicalTrials.gov number, NCT00223080.)
Rerks-Ngarm
Supachai
S
Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand.
Pitisuttithum
Punnee
P
Nitayaphan
Sorachai
S
Kaewkungwal
Jaranit
J
Chiu
Joseph
J
Paris
Robert
R
Premsri
Nakorn
N
Namwat
Chawetsan
C
de Souza
Mark
M
Adams
Elizabeth
E
Benenson
Michael
M
Gurunathan
Sanjay
S
Tartaglia
Jim
J
McNeil
John G
JG
Francis
Donald P
DP
Stablein
Donald
D
Birx
Deborah L
DL
Chunsuttiwat
Supamit
S
Khamboonruang
Chirasak
C
Thongcharoen
Prasert
P
Robb
Merlin L
ML
Michael
Nelson L
NL
Kunasol
Prayura
P
Kim
Jerome H
JH
D016915:AIDS Vaccines / Q000009:adverse effects / Q000276:immunology; D000328:Adult; D018791:CD4 Lymphocyte Count; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D015483:HIV Antibodies / Q000097:blood; D015699:HIV Envelope Protein gp120 / Q000276:immunology; D015658:HIV Infections / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D015497:HIV-1 / Q000276:immunology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D016016:Proportional Hazards Models; D013785:Thailand; D016896:Treatment Outcome; D019562:Viral Load; D055815:Young Adult
D016915:AIDS Vaccines; C112734:AIDSVAX; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120