Barth-Jones D, Chick S, Adams A, Koopman J; International Conference on AIDS.
Int Conf AIDS. 2000 Jul 9-14; 13: abstract no. MoOrC126.
D. Barth-Jones, Wayne State University, School of Medicine, Center for Healthcare Effectiveness Research, 121 Shiffman Medical Library, 4325 Brush, Detroit, MI, USA 48201, United States, Tel.: +1 313 577 8387, Fax: +1 313 577 1773, E-mail: barthjon@umich.edu
Background: It is of considerable importance that HIV vaccine trials be designed to measure vaccine effects (VE) on both susceptibility and infectiousness, so as to determine the full impact that vaccination could have on the basic reproduction number (Ro) of the HIV epidemic. This will be particularly important when vaccines have weak susceptibility effects, yet significantly decrease the infectiousness of those individuals who are infected despite vaccination. Under such circumstances, failure to measure infectiousness effects could lead to the rejection of HIV vaccines which are capable of halting the HIV epidemic. The Retrospective Partner Trials (RPT) HIV vaccine trial measures: 1) VE on Susceptibility (VES), 2) VE on Infectiousness (VEI), and 3) VE on Ro (VER) by retrospectively obtaining phylogenetic HIV data from contact-traceable sexual partners of vaccine trial subjects. Methods: A discrete-event Monte Carlo computer simulation of a homosexual mixing population was used to evaluate the bias, precision, and statistical power for the VES, VEI, and VER estimates produced by the RPT design. For each VE estimator, the bias, standard error and statistical power were evaluated as VES, VEI, and the vaccine trial sample sizes were varied. Results: At sample sizes similar to the Phase III HIV vaccine trials currently being conducted in Thailand and the United States (N = 2,500-5,000), the RPT design was found to produce VE estimates with little bias, high precision and excellent statistical power. Conclusions: The results of this simulation experiment indicate that under appropriate conditions, the RPT vaccine trial design is capable of producing accurate estimates of actual VES, VEI and VER effects using realistic sample sizes. Because VEI and VER have great public health importance, the RPT design should receive consideration for future HIV vaccine evaluations.
Publication Types:
Keywords:
- AIDS Vaccines
- Acquired Immunodeficiency Syndrome
- Clinical Trials as Topic
- Clinical Trials, Phase III as Topic
- Computer Simulation
- Disease Susceptibility
- HIV
- HIV Infections
- HIV Seropositivity
- Research Design
- Sample Size
- Sexual Partners
- Thailand
- United States
- Vaccination
- Vaccines
- pathogenicity
Other ID:
UI: 102237917
From Meeting Abstracts