Abstract
BackgroundThe AIDS epidemic in Brazil remains concentrated in populations with high vulnerability to HIV infection, and the development of an HIV vaccine could make an important contribution to prevention. This study modeled the HIV epidemic and estimated the potential impact of an HIV vaccine on the number of new infections, deaths due to AIDS and the number of people receiving ARV treatment, under various scenarios.Methods and FindingsThe historical HIV prevalence was modeled using Spectrum and projections were made from 2010 to 2050 to study the impact of an HIV vaccine with 40% to 70% efficacy, and 80% coverage of adult population, specific groups such as MSM, IDU, commercial sex workers and their partners, and 15 year olds. The possibility of disinhibition after vaccination, neglecting medium- and high-risk groups, and a disease-modifying vaccine were also considered. The number of new infections and deaths were reduced by 73% and 30%, respectively, by 2050, when 80% of adult population aged 15–49 was vaccinated with a 40% efficacy vaccine. Vaccinating medium- and high-risk groups reduced new infections by 52% and deaths by 21%. A vaccine with 70% efficacy produced a great decline in new infections and deaths. Neglecting medium- and high-risk population groups as well as disinhibition of vaccinated population reduced the impact or even increased the number of new infections. Disease-modifying vaccine also contributed to reducing AIDS deaths, the need for ART and new HIV infections.ConclusionsEven in a country with a concentrated epidemic and high levels of ARV coverage, such as Brazil, moderate efficacy vaccines as part of a comprehensive package of treatment and prevention could have a major impact on preventing new HIV infections and AIDS deaths, as well as reducing the number of people on ARV. Targeted vaccination strategies may be highly effective and cost-beneficial.
Highlights
After 30 years the AIDS pandemic continues to compromise the health, quality of life and productivity of populations, and significantly affects economies as well as societal and family structures
Even in a country with a concentrated epidemic and high levels of ARV coverage, such as Brazil, moderate efficacy vaccines as part of a comprehensive package of treatment and prevention could have a major impact on preventing new HIV infections and AIDS deaths, as well as reducing the number of people on ARV
This study looked at the potential impact of diverse vaccination strategies, including vaccinating the general adult population, aged 15–49; vaccinating 15-year-old adolescents; and vaccinating medium- and high-risk groups, defined as men who have sex with men (MSM), injecting drug users (IDU), and commercial sex workers and their partners
Summary
After 30 years the AIDS pandemic continues to compromise the health, quality of life and productivity of populations, and significantly affects economies as well as societal and family structures. The epidemic in Brazil remains concentrated amongst populations with increased vulnerability to HIV infection [1], more than 500,000 AIDS cases and 200,000 AIDS deaths have been reported by 2008 [2]. To address the challenge of continued HIV transmission as well as increasing treatment needs, the Brazilian government has prioritized prevention efforts [3,4], and has implemented a broad treatment and care program throughout the five geographical regions in the country. The AIDS epidemic in Brazil remains concentrated in populations with high vulnerability to HIV infection, and the development of an HIV vaccine could make an important contribution to prevention. This study modeled the HIV epidemic and estimated the potential impact of an HIV vaccine on the number of new infections, deaths due to AIDS and the number of people receiving ARV treatment, under various scenarios
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