HIV Vaccine "Essential" to Ending AIDS Pandemic
Research published this week makes the case that even a “modestly effective” HIV vaccine would be “cost-effective” and “contribute strongly to a sustained HIV/AIDS response.
The research was conducted by the International AIDS Vaccine Initiative (IAVI), in partnership with AVAC, which advocates for a vaccine, and Avenir Health, which helps implement costing models for long-term planning for public health events such as vaccine rollouts. The paper appears in the current edition of PLOS ONE.
The paper used an epidemiological model to explore how a vaccine might impact low- and middle-income countries in combination with other inventions through 2070. “Assumptions were based on perspectives from research, vaccination and public health experts, as well as observations from other HIV/AIDS interventions and vaccination programs,” the abstract states. “Sensitivity analysis varied vaccine efficacy, duration of protection, coverage, and cost.”
Critics abound as to whether money funneled toward an HIV vaccine is money well spent. Many argue that by the very nature of the disease itself, finding a vaccine that works long-term is an enormous task. The authors acknowledge that in the paper.
“Developing an AIDS vaccine is a huge scientific challenge,” they wrote. “HIV mutates very rapidly, allowing the virus to escape the body’s immune responses while giving rise to multiple clades (strains) that circulate around the globe. Further, HIV establishes persistent infection quickly following transmission, suggesting that the opportunity to prevent or abort an infection is short-lived.”
The authors concede that, “Of the few vaccine candidates that have progressed to late-stage clinical trials, most have failed to demonstrate efficacy. In 2009, combining the ALVAC and AIDSVAX candidates reduced new infections by 31 percent after three years of follow-up the Phase III RV 144 trial in Thailand. An efficacy study of a redesigned version of this candidate is planned to start in late 2016 in South Africa, including modification to clade C, a new protein boost, different adjuvants, and additional booster shots intended to improve both strength and durability of protection. In addition, there are currently more than 30 earlier stage clinical studies underway around the world to investigate other vaccine candidates aiming at eliciting strong, broad and lasting efficacy.”
Infectious disease expert Dr. Amesh Adalja told HIV Equal it’s important to note that there has not been a vaccine developed that fits the assumption of the model, but nonetheless, “The study is important in that it quantifies how a moderately protective vaccine could change the face of the HIV pandemic above and beyond standard control measures. Such a study should provide further motivation to improve vaccine research and development to substantially augment the efficacy of vaccines being developed because, as is clear with many infectious diseases, a vaccine-based approach is essential to end the pandemic.”
In a news release, AVAC Executive Director Mitchell Warren made a similar point: The pandemic will not end without a vaccine. “Adding a vaccine to a comprehensive HIV response will hasten the end of the global epidemic and ensure that it won’t rebound. A safe, effective, and affordable HIV vaccine is an essential complement to the existing treatment and prevention options, and this study highlights why accelerated investments are needed for both implementation of what we have and the development of what we still need.”
In the study, the authors also acknowledged that “characteristics of an eventual AIDS vaccine and of vaccination programs remain unknown” and were not based on any particular AIDS vaccine in the pipeline. “Our assumptions seek to carefully balance the potential promise of a vaccine against the remaining scientific challenges in AIDS vaccine research and development, the potential evolution of the broader HIV/AIDS response, the structural realities in relevant health care systems and the potential issues in sustainably reaching target populations, which may be further influenced by vaccine efficacy, required number of doses, costs, and duration of protection.”
Meanwhile, UNAIDS continues to advocate for its ambitious “90/90/90” goal as an approach to getting to zero new infections. The goal calls for 90 percent of all people with HIV knowing their status, being on antiretroviral therapy, and having viral suppression by 2020.
In another epidemiological analysis released this week, researchers showed that two-thirds of new HIV infections in the Netherlands could be prevented if all men who have sex with men are tested annually for HIV, given antiretroviral therapy immediately if they test positive, and if half of HIV-negative men go on PrEP.
The research was published in Science Translational Medicine and was a retroactive analysis of Dutch infections.