Two major thrusts

Going forward, says Michael, there will be two major thrusts in terms of vaccine research. One will be a follow-up study to RV144, conducted by the Army with the National Institutes of Health, in different risk groups and geographic locations. “It is a great example of interagency coordination and synergy,” he says, noting that the Army will only conduct a portion of the next efficacy studies.

“Many of us are also working on a universal vaccine, which uses genetic approaches, so that theoretically one could work for all subtypes,” he continues. While many experts note that it is not possible to develop a single cure for cancer because there are so many different types of disease, a “mosaic” vaccine is theoretically possible for a virus such as HIV. Besides, says Michael, it would be extremely hard for a pharmaceutical company to develop different vaccines, for example, for HIV subtypes in the U.S., Australia, and Southern Africa. “And East Africa is a real alphabet soup (i.e, subtyped A, C, D, and mixtures of the three); it’s very complex,” he adds.  

At present, Michael says, most researchers are looking at vaccines tailored to a single subtype. “We want to be able to begin to develop a firm foundation that a vaccine of this type could work in all countries and against all types – heterosexuals, men, women, and so on,” Michael declares. “We want a global health solution.”

There is some promising research along such lines, says Kim. For example, animal models now show protection against acquisition.  But the goal is to have an animal model and a human model that inform each other, and, “We’re not there yet,” Kim explains. For example, the RV144 showed modest efficacy in infection, but if an individual got infected, researchers did not see any change in the amount of virus in the blood or T cells compared to placebo. It did not seem to affect the course of the disease, whereas a new vaccine being tested in a collaboration between the Army and Dr. Dan Barouch of Harvard appears to do so in monkeys.

“A combination of the Ad-26 (adenovirus serotype 26) and the MVA (modified vaccinia Ankara) vectors with SIV inserts as a prime-boost combined to give protection of monkeys against both infection, which is good, and also, those monkeys that received the vaccine and became infected have a great delay in disease progression – that’s tremendous,” says Kim. Human studies should begin next year, he adds, with advanced testing hopefully taking place between 2013 and 2015.

The best-case scenario, says Michael, would be a vaccine in about 10 years; it will take about six years for full efficacy studies of RV144, and progress on a universal vaccine is three years behind that, he notes.

“If I had it in hand right now I’d give it to every high-risk individual,” he says, adding that he would not necessarily recommend that all servicemembers receive the vaccine. “If they are being deployed to a part of the world where the risk is higher, that’s who should get it,” he explains. “Those would be the kind of thought-processes military medical activities employ when thinking about who should be vaccinated.”

Armed Forces Health Surveillance Centers’ Medical Surveillance Monthly Report

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