Yale University

Predicting the impact of a partially effective HIV vaccine and subsequent risk behavior change on the heterosexual HIV epidemic in low- and middle-income countries: A South African example.

TitlePredicting the impact of a partially effective HIV vaccine and subsequent risk behavior change on the heterosexual HIV epidemic in low- and middle-income countries: A South African example.
Publication TypeJournal Article
Year of Publication2007
AuthorsAndersson, Kyeen M., Douglas K. Owens, Eftyhia Vardas, Glenda E. Gray, James A. McIntyre, and David A. Paltiel
JournalJournal of acquired immune deficiency syndromes (1999)
Volume46
Issue1
Pagination78-90
Date Published2007 Sep 1
ISSN1525-4135
KeywordsAIDS Vaccines, Computer Simulation, Condoms, Female, HIV Infections, Humans, Male, Models, Biological, Risk Factors, Sensitivity and Specificity, Sex Factors, Socioeconomic Factors, South Africa, Time Factors, Unsafe Sex
AbstractWe developed a mathematical model to simulate the impact of various partially effective preventive HIV vaccination scenarios in a population at high risk for heterosexually transmitted HIV. We considered an adult population defined by gender (male/female), disease stage (HIV-negative, HIV-positive, AIDS, and death), and vaccination status (unvaccinated/vaccinated) in Soweto, South Africa. Input data included initial HIV prevalence of 20% (women) and 12% (men), vaccination coverage of 75%, and exclusive male negotiation of condom use. We explored how changes in vaccine efficacy and postvaccination condom use would affect HIV prevalence and total HIV infections prevented over a 10-year period. In the base-case scenario, a 40% effective HIV vaccine would avert 61,000 infections and reduce future HIV prevalence from 20% to 13%. A 25% increase (or decrease) in condom use among vaccinated individuals would instead avert 75,000 (or only 46,000) infections and reduce the HIV prevalence to 12% (or only 15%). Furthermore, certain combinations of increased risk behavior and vaccines with <43% efficacy could worsen the epidemic. Even modestly effective HIV vaccines can confer enormous benefits in terms of HIV infections averted and decreased HIV prevalence. However, programs to reduce risk behavior may be important components of successful vaccination campaigns.
DOI10.1111/j.1524-4733.2010.00763.x
Alternate JournalJ. Acquir. Immune Defic. Syndr.