One curious finding showed that the vaccine induced very few antibodies. Most vaccines consist of parts of a virus or bacterium that prompt the immune system to make antibodies, which then protect the body by attacking the invading pathogen.
The chief usefulness of the ALVAC-AIDSVAX vaccine will probably be what it can teach infectious-disease researchers about what is happening in the immune system when a person is even somewhat protected against HIV, the Washington Post reported.
"We really need to go through the data to see if there are effects here that are potentially useful," Kim said.
He predicted that information gained from the trial after the results are fully analyzed will have "important implications for the design of future HIV vaccines," the Post reported.
Fauci stressed that the new trial results do not mark "the end of the road," but he was surprised and pleased by the outcome, the AP reported.
"It gives me cautious optimism about the possibility of improving this result" and developing a more effective AIDS vaccine, he said. "This is something that we can do."
Leaders in the search for an AIDS vaccine were also heartened by the news.
Dr. Alan Bernstein, executive director of the Global HIV Vaccine Enterprise in New York City, said, "The results themselves are modest: 30 percent protection is not a level of protection that we can actually go out and give to people, but it's a landmark day because it says that achieving protection in humans against HIV with an HIV vaccine is possible."
"It's going to be so exciting over the next few years to go from 30 percent protection to 100 percent protection," he added.
Rowena Johnston, director of research for the Foundation for AIDS Research, New York City, added, "This is an important step, it's an encouraging step, but it is not the final step."
"These results are interesting from the perspective of what we are going to learn out of them," she said. "There are probably few people who would say this is the product we should be making available to people around the world. But it is showing us directions in which we might look."
Seth Berkley, president and chief executive officer of the International AIDS Vaccine Initiative, said in a prepared statement: "It's the first demonstration that a candidate AIDS vaccine provides benefit in humans. Until now, we've had evidence of feasibility for an AIDS vaccine in animal models. Now, we've got a vaccine candidate that appears to show a protective effect in humans, albeit partially."
In 2007, 33 million people around the world were living with HIV/AIDS. More than 64.9 million people have been infected with HIV since the pandemic began. AIDS is the leading cause of death in sub-Saharan Africa, and the fourth leading cause of death globally, according to the U.S. Agency for International Development.
ALVAC is made by Sanofi Pasteur, the vaccine division of French drugmaker Sanofi-Aventis. AIDSVAX was originally developed by VaxGen Inc., and the patent is now held by Global Solutions for Infectious Diseases, a nonprofit group founded by some former VaxGen employees, AP reported.
In addition to the two vaccine patent holders and the U.S. National Institute of Allergy and Infectious Diseases, participants in the Thai trial included the United States Army, and the Thai Ministry of Public Health, the Times reported.
More information on the trial will be presented at an AIDS vaccine meeting in Paris later this fall, the Post reported.
To learn more about HIV and AIDS, visit the U.S. Centers for Disease Control and Prevention.
SOURCES: Alan Bernstein, M.D., executive director, Global HIV Vaccine Enterprise, New York City; Rowena Johnston, Ph.D., director of research, Foundation for AIDS Research, New York City; Sept. 24, 2009, news release, Global HIV Vaccine Enterprise; Sept. 24, 2009, news release, International AIDS Vaccine Initiative; Associated Press; The New York Times; Washington Post