- The Washington Times - Friday, September 25, 2009

For the first time, researchers have created a vaccine that managed in clinical trials to lower significantly the risk of infection by the virus that causes AIDS - in this case, by about one-third over three years.

Lt. Gen. Eric Schoonmaker, U.S. Army surgeon general, announced the results at the Army’s division of retrovirology in Silver Spring, calling the news “very exciting” and an outstanding success story made possible through an unusual degree of international cooperation between public and private organizations and volunteers.

“The basic discovery from the standpoint of science was showing that it is possible to make a vaccine to block transmission of this virus,” said Col. Nelson Michael, director of the Army’s division of retrovirology, which spearheaded the work.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, the major funder of the $105 million study, said the results surprised him because it has long been thought that making a vaccine against a virus that attacks the immune system is impossible.

But he cautioned against expecting too much too soon, saying that scientists don’t yet know the reason for the success of this vaccination regimen - a mix of two drugs that had failed clinical trials when given on their own.

“Even though the effect was modest, at least we know something about the fundamental process,” Dr. Fauci told The Washington Times. “Now we need to learn what was the nature of the response.”

When tested previously, the vaccines - ALVAC from Sanofi Pasteur and AIDSVAX from Global Solutions for Infectious Diseases - were not effective on their own. And an earlier trial involving a drug made by Merck & Co. Inc. had adverse results among its participants - high-risk U.S. men and women.

“The field was stopped in its tracks and looked even like another trial could cause harm,” Col. Michael said.

The 16,000 Thai volunteers in this case, he emphasized in an interview, came from “moderate-risk communities,” which meant that this trial went ahead because even if the drugs were ineffective, increased transmission of HIV likely would not result.

“The caveat, even in such a large study like this, is you only got about a one-third reduction in risk and it was done in Thailand where there are unique types of HIV that circulate. You have to ask yourself if you took the same vaccine and tried it in Africa or the U.S., would you get the same result?” Col. Michael said.

The typical benchmark in medicine is that a vaccine should protect 80 percent or more of the recipients. And while this vaccine’s 31.2 percent rate doesn’t come close, considering the failure of previous HIV vaccines, “you would say that is a great start.”

“The next step is detecting out the genetic component that might have contributed to protection. All vaccines work differently in different people,” he said.

Starting in 2003, the Thai study involved more than 16,000 HIV-negative volunteers in Thailand - both sexes, ages 18 to 30 - with half receiving a vaccine treatment over six months and half a placebo, and then all being followed for three years.

The Army did the test in Thailand partly to protect U.S. soldiers who travel there and partly because the Thai government is more cooperative than some other governments.

“The Army has a very large program in HIV and other diseases around the world. The good thing about this is by protecting our troops, we are also doing something for mankind,” Col. Michael said.

The finding, which still is in an experimental phase, holds promise for protection against one of the world’s most intractable diseases, which has killed 25 million people since first being identified in the early 1980s.

There is no known cure for AIDS. The International AIDS Vaccine Initiative estimates that such a vaccine would prevent 5.6 million new infections in low- and middle-income countries between 2015 and 2030 if it were given to 30 percent of the population.

The group says 18 other vaccines are being studied in clinical trials.

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