Is there a Cure on the Horizon?
According to the World Health Organization, since the AIDS epidemic began, nearly 22 million adults and children have died. Every day, 15,000 people become infected with the HIV virus. AIDS is the leading cause of death in Africa and the fourth leading cause of death worldwide.
The Centers for Disease Control and Prevention estimates that there are about 1 million Americans who have HIV/AIDS, and about half are not receiving medical care, primarily because they don’t know they have the virus.
Progress in developing a vaccine that prevents AIDS has been slow and disappointing to many in the medical field. There’s no single reason why there’s not a vaccine yet. First of all, the virus itself is challenging. There are nine subtypes of the HIV virus. These differ from each other by 30 to 35 percent, so it’s difficult to create a vaccine that would work on each subtype. And to make matters even more complex, the HIV virus mutates, or changes, once it’s inside the body. This makes it hard for the immune system to destroy it; it’s almost like shooting at a moving target.
Some people active in the push for development of a vaccine believe that there’s been resistance to vaccine research because of the stigma associated with the disease. Others believe that since there are now drugs that can keep the disease at bay for a long time, many people think of it as a chronic condition that people just have to learn to live with.
In the developing world, a vaccine that prevents AIDS would be the best hope in the fight against the disease. Developed countries have had the advantage of well-organized educational campaigns about preventing the spread of the HIV virus. They’ve also had access to effective treatments. This kind of education and treatment has not been available in places such as Africa, where HIV/AIDS cases have been increasing every year. At the International AIDS conference in Barcelona, Spain this past summer, it was reported that the average life expectancy of people in 11 African countries will drop below 40 in 2010. In one African country alone, Botswana, nearly half of the adults are infected with HIV.
Researchers are working on developing two types of vaccines for HIV/AIDS. One would be what’s called a “preventive” vaccine. It would protect people from becoming infected with the virus in the first place. The other type is called a “therapeutic” vaccine. For people who already have HIV, it would help the immune system recognize and rid the body of the virus.
In July 2002 U.S. health authorities announced that the U.S. National Institute of Allergy and Infectious Diseases (NIAID) and the Thai Ministry of Public Health will co-sponsor a $36 million trial for an AIDS vaccine. It’s the largest trial ever conducted. It will take place in Thailand, and there will be about 16,000 HIV-negative volunteer participants in the trial. Half of them will receive three primer shots and two booster shots over a six-month period. The other half will receive placebos (sugar pills). The primer is made by Aventis Pasteur, and the booster is made by VaxGen.
Final analysis of trial results is expected to take place in 2008.
The NIAID is also conducting clinical trials of the first AIDS vaccine that is directed at the three most common subtypes of the HIV virus. The first phase of the trial is being conducted at the National Institutes of Health in Bethesda, Maryland. It will enroll 50 healthy, HIV-negative volunteers. Expanded trials are planned for additional sites in the U.S. and for sites in Haiti and Africa.
Centers for Disease Control and Prevention; National Institute of Allergy and Infectious Diseases; International AIDS Vaccine Initiative; World Health Organization