Purpose: A successful prophylactic HIV vaccine will probably require neutralizing antibodies and vigorous CTL (CD8+ T-cytotoxic lymphocyte) responses. Canarypox vector-based HIV vaccines (ALVAC-HIV) have been gaining momentum as promising HIV vaccine candidates because of their ability to elicit CTL responses. This quantitative meta-analysis was undertaken to determine a summary estimate of CTL responses to ALVAC-HIV vaccines in HIV-1 seronegative volunteers and to identify reasons for differences among studies in the estimated effects on CTL responses.
Method: After a literature search and data abstraction, eight randomized, double-blind, placebo-controlled studies were selected for meta-analysis. Stratified and random effects meta-regression analyses were performed to search for response differences among studies.
Results: Of the various study characteristics, the number of immunizations and the vaccine dose were associated with the likelihood of developing CTL responses. It was not possible to distinguish the effect of either the number of immunizations or the vaccine dose on CTL responses because these two study characteristics were highly associated with each other.
Conclusion: More trials are warranted to determine the ideal dose/immunization schedule that would elicit maximal CTL responses.