The Atlanta Journal-Constitution
Trials have scientists hopeful for HIV vaccine
First there were the drugs that could knock back HIV to undetectable levels, and the virus was no longer synonymous with a death sentence. Then came a treatment that allowed people who were HIV-negative to remain that way, even if their partners weren’t. But to truly defeat the virus that causes AIDS, doctors need a vaccine. And after decades of dead ends and dashed hopes, they may finally be on the verge of having one.
What’s happening
With a large-scale clinical trial launching this fall and several others already underway, scientists say they are cautiously optimistic that they’ll soon have a way to fight HIV long before a person is ever exposed.
“When you have a disease that is transmitted without symptoms, you’re going to acquire it when you least expect it,” said Dr. Larry Corey, principal investigator of the HIV Vaccine Trials Network. In such situations, “the only base control measure ever proven to be effective is a vaccine.”
Researchers and public health experts agree that the surest way to eliminate a disease for good is by deploying a vaccine. It worked for smallpox. It worked for polio. And, if combined with antiretroviral therapy and preexposure prophylaxis, it could work for HIV too.
Why it matters
A vaccine would mean “the end of the AIDS story as we know it,” said Dr. Robert C. Gallo, director of the Institute of Human Virology at the University of Maryland School of Medicine.
More than 37 million people around the world are living with HIV, and they spread it to about 5,000 others every day, Corey said. There are also about 180,000 transmissions to newborns each year.
“This virus is unfortunately doing very well,” he said.
The human immunodeficiency virus, or HIV, attacks a specific type of white blood cell the body relies on to fight off infections. If left untreated for several years, a patient’s white blood cell count becomes critically low, leading to acquired immunodeficiency syndrome, or AIDS. That makes the body vulnerable to bacteria and fungi that can cause tuberculosis, meningitis, certain types of cancer and other serious diseases that can lead to death.
With classic threats such as measles or polio, the vast majority of people are already able to suppress the virus and eradicate it from their bodies. In those cases, developing a vaccine is as simple as finding a safe way to mimic a natural infection — perhaps by introducing a modified version that has been stripped of its weaponry.
But HIV is different, because no patient has ever been known to overcome the virus on his or her own.
What’s next
In preclinical trials, the vaccine effectively protected about 66% of nonhuman primates against HIV-like viruses. Follow-up studies in people helped finalize its makeup. Now scientists plan to enroll some 3,800 healthy participants at more than 50 trial sites across North and South America and Europe. All of them will be drawn from groups that are at high risk of contracting HIV, including men who have sex with men and transgender people. They will receive four vaccinations over the course of a year.
The study will be double-blind, meaning neither the participants nor the researchers will know who has been selected to receive the vaccine and who is getting a placebo. If the vaccine proves successful, researchers hope it will be used around the world.