How Close Are We to an Effective HIV Vaccine?

"We're a decade away," says Mitchell Warren, Executive Director of the AIDS Vaccine Advocacy Coalition. "It just depends on when you start the clock."

HIV vaccine science is incredibly complicated, particularly given HIV's elusiveness and ability to mutate rapidly. Not to mention that we're still trying to fully understand how HIV infects humans and how our immune system works. To share knowledge and discuss the latest developments in the field, researchers from all over the world have gathered this week in Barcelona, Spain, for the 13th annual AIDS Vaccine conference.

The scientific keys to a successful HIV vaccine are still: finding the right vector (an attenuated version of a different virus that's been modified or engineered to "look" like HIV) and eliciting the right immune response (one particular approach involves using broadly neutralizing antibodies, which can identify and target a wide range of viruses, including HIV).

An effective vaccine would only be one part of the combination prevention arsenal, experts remind us. That arsenal now includes treatment as prevention, pre-exposure prophylaxis, prevention of mother-to-child transmission, treatment for sexually transmitted infections that increase the risk of HIV transmission, condoms, male circumcision, microbicides, HIV testing and counseling, drug and alcohol treatment, harm reduction, blood screening and general HIV education.

At AIDS Vaccine 2013, Jim Maynard and Steve Wakefield of the HIV Vaccine Trials Network emphasized the importance of vaccine trials and recruiting trial participants; they also highlighted the lack of education that still exists. The No. 1 misconception that people have is that a vaccine candidate might infect them with HIV, they said. This is simply not true, because vaccine candidates are engineered to "look" like HIV, but do not actually contain HIV, they explained.

Even though HIV vaccine science continues to progress, people still aren't using the prevention methods that are already available, Wakefield said. He shared common reasons people have for not using condoms, such as, "He was really cute," "He told me he loved me," or "I got an HIV test last week." But as Wakefield pointed out, "Love and an HIV test don't protect us against infection."

In addition, experts here noted that some HIV prevention methods need to be better developed to be more practical and easier to use. In particular, microbicide gels for women can be cumbersome to adhere to, as highlighted by the low adherence levels in the VOICE study. An effective prevention tool will need to take into account the needs of women, Glenda Gray, Executive Director of the Perinatal HIV Research Unit and Associate Professor of Pediatrics at the University of the Witwatersrand in South Africa, pointed out at a satellite symposium. "Nobody wants to apply vaginal gel and have wet panties all day," Gray remarked.

We're still years away from an HIV vaccine, but hopefully, when it gets here, it will cut new HIV infections significantly. Even if current global HIV prevention funding stays stagnant, a vaccine with a significant level of efficacy would reduce HIV incidence by at least half, Margaret McGlynn, President and Chief Executive Officer of the International AIDS Vaccine Initiative, stated at the same symposium.

We have many great HIV prevention tools, but if we really want to get to zero and stay at zero, we'll need an HIV vaccine, McGlynn concluded.