Model Suggests HIV Vaccine Could Play Key Role in Ending AIDS

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Even a modestly effective HIV vaccine would likely be cost-effective and could make a major contribution to a sustainable response to the global HIV/AIDS epidemic, especially in combination with the scale-up of other interventions including prompt antiretroviral therapy (ART) and pre-exposure prophylaxis (PrEP), according to a report in the January 5 edition of PLoS ONE.

Prevention approaches including condoms, antiretroviral treatment as prevention (TasP), and PrEP have already brought about substantial reductions in new HIV infections, but there are still too many people becoming infected worldwide to bring the epidemic to a halt.

Thomas Harmon of the International AIDS Vaccine Initiative (IAVI) and colleagues performed a modeling study to estimate the impact of an HIV vaccine, combined with interventions included in the UNAIDS Investment Framework Enhanced (IFE), in low- and middle-income countries.

The IFE, proposed in 2013, explored how maximizing existing interventions and adding emerging prevention options could reduce new HIV infections and AIDS-related deaths in low- and middle-income countries, the authors noted as background. This report describes additional modeling that looked more closely at the potential health impact and cost-effectiveness of HIV vaccines.

The researchers devised anepidemiological model to explore the potential impact of HIV vaccination in low- and middle-income countries in combination with other interventions through 2070. Sensitivity analyses looked at variations in vaccine efficacy, duration of protection, coverage, and cost.

The model looked at 3 possible scenarios:

Results

"Even a modestly effective vaccine could contribute strongly to a sustainable response to HIV/AIDS and be cost-effective, even with optimistic assumptions about other interventions," the study authors concluded. "Higher efficacy would provide even greater impact and cost-effectiveness, and would support broader access."

"First generation AIDS vaccines may not achieve the very high efficacy levels of most other currently licensed vaccines, and structural, cultural, and social barriers may make it challenging to meet assumed coverage rates for some target populations," they caution, "but the model shows that vaccines of relatively lower efficacy and uptake still have the potential to substantially reduce new HIV infections."

"The data suggest that under certain circumstances vaccination could prevent more new infections with HIV than other new prevention options," they wrote. "However, the modeling also confirms that no single option can solve the problem alone. A variety of prevention and treatment options can complement each other in ensuring that the specific needs of specific populations in different circumstances are met in order to maximize the reduction of new HIV infections."

"These new analyses underscore the powerful potential of an AIDS vaccine to help save and improve the lives of millions in a cost-effective manner," IAVI president and CEO Mark Feinberg stated in a press release. "It is clear that we must continue to expedite development of an effective HIV vaccine alongside the critical efforts to accelerate and sustain broad and equitable access to effective antiretroviral therapy and new approaches for pre-exposure prophylaxis."

1/20/16

Reference

TM Harmon, KA Fisher, MG McGlynn, et al. Exploring the Potential Health Impact and Cost-Effectiveness of AIDS Vaccine within a Comprehensive HIV/AIDS Response in Low- and Middle-Income Countries. PLoS ONE. January 5, 2016.

Other Source

International AIDS Vaccine Initiative. Modeling Shows a Vaccine Is Essential to Conclusively Ending HIV/AIDS. Press release. January 5, 2016.