The AIDS Vaccine 2011 conference ended Thursday in Bangkok, Thailand. While a vaccine to help end the pandemic remains elusive, scientific advances are being made.

About 850 scientists, researchers and others met for four days to discuss progress on finding a vaccine to prevent HIV infection. It's the only conference to focus exclusively on that.

Exciting time

Mitchell Warren, head of the AIDS Vaccine Advocacy Coalition, or AVAC, gives the meeting fairly high marks.

"I'd say on a scale from one to ten, we are in a scientific zone in the upper sevens and eights," he said.

AVAC is a non-profit organization with a stated goal speeding up the "ethical development and delivery of AIDS vaccines" as part of a "comprehensive response to the pandemic."

AIDS Vaccine 2010Mitchell Warren of AVAC

"We are in a terrific moment in the field and I must say it is terrifically exciting to be able to do this meeting here in Bangkok. It's not just good science, but to be in the country where the largest AIDS vaccine trial in the world took place - and the first trial to demonstrate that a vaccine was possible – it's pretty exciting timing," he said.

That vaccine candidate is known as RV-144. The results of the trial involving about 16,000 participants were announced in 2009. They showed a protection rate of about 31 percent - not nearly good enough to go to market, but good enough to show it can be done.

Now what?

Warren said, "Over the last two years, an unprecedented international collaboration has been underway to try to understand why we got the modest effect in that trial that we did."

What they found were not definite answers, but rather new signals of what direction to take next.

"It is what we call hypothesis generating and there is going to need to be some additional studies to confirm that. But these are the first signals we've ever had," he said.

A follow-up trial to RV-144 will be held in 2014. It will reflect new the data and direction developed since 2009.

Meanwhile, there is a vaccine trial that's currently recruiting 2,200 participants in about 20 U.S. cities. It's sponsored by the HIV Vaccine Trials Network. HVTN 505 is the world's largest ongoing HIV vaccine study and uses a combination of two experimental vaccines. It will focus on preventing infection among men who have sex with men and transgender women.

"While this is one of the most exciting times in our field, it is also the most complex time in our field. These are complexities and challenges that we've longed for. I think it's safe to say that vaccine trials are going to get more complicated, but more interesting in the next couple of years," said Warren.

Three-part strategy

He added that in these difficult economic times, a comprehensive strategic plan is needed for HIV/AIDS. The near and midterm strategies, he says, should include scaling up treatment and care, condoms, male circumcision, microbicides and the use of antiretroviral drugs as a preventive measure. The long term strategy is an AIDS vaccine.

"The near term and midterm strategies are the ones that are going to help us begin to control the epidemic. The long term strategy will get us an end to the epidemic," he said.

AIDS Vaccine 2012 will be held next September in Boston, Massachusetts.