An average of one person per household is infected with HIV, including 29 percent of pregnant women.
"It's a monster that swallows young and old, rich and poor," Khumalo told a gathering of AIDS experts yesterday at Morgan State University.
"Our only hope of protecting future generations is a vaccine."
Two years after President Clinton came to the Northeast Baltimore campus and vowed to achieve an AIDS vaccine within a decade, scientists say there are promising signs that a vaccine is feasible.
The first large-scale trial of an experimental vaccine in a high-risk population has been launched in Baltimore and 30 other U.S. cities.
But beyond science, formidable practical obstacles -- from unwarranted fears of vaccines to apharmaceutical industry wary of legal hazards and uncertain profits -- remain to defeating AIDS with immunization, the experts said.
Despite huge progress in treating AIDS patients in the United States and the rest of the developed world, the medication cocktails that have reduced deaths here are far too expensive for the Third World.
Millions dead or infected
With 16,000 people infected with HIV every day worldwide, the AIDS epidemic is undoing a half-century of progress in international public health, the scientists said.
Nearly 14 million people have died of AIDS worldwide and 33.4 million are infected with HIV, a number that grew by nearly 6 million last year.
In a half-dozen of the hardest-hit African countries, life expectancy has declined from more than 60 years to less than 40 years.
Much of Asia is following the same curve, with more infected people in India today than in any other country.
"You're seeing the equivalent of the plague, and it's the end of the 20th century," said Dr. Seth Berkley, president of the International AIDS Vaccine Initiative in New York, referring to the Black Death that cut Europe's population in half in the 14th century.
Yet of nearly $20 billion spent on AIDS worldwide each year, only a little more than 1 percent goes to finding a vaccine, Berkley said.
Most of that money is U.S. government grants to academic research centers, which have been struggling to find an immunization that protects against the constantly mutating virus.
The entire commercial drug industry remains largely unwilling to invest in a vaccine, Berkley said.
The science of an AIDS vaccine requires a big, long-term investment. With 95 percent of HIV infections in the developing world, there is no guarantee of a large market of paying customers.
Meanwhile, drug companies worry about courting ethical and legal trouble. If they invest millions and produce a vaccine, they will face intense pressure to make it available cheaply to Third World countries and never recoup their investment.
"That's a big scare in the industry," Berkley said.
When it does attract financial support, vaccine development faces other problems.
A test of the protective effect of an experimental vaccine -- called a Phase III trial -- requires that thousands of uninfected, high-risk people be given the vaccine.
Then the rate of new infections in the vaccinated group is compared with the rate in a control group that gets a placebo.
But to get a clear result, the vaccine volunteers must come from a group with a very high rate of new infections.
Such populations are found only in the Third World, where practical difficulties of organizing vaccine trials are daunting.
Only one trial is under way in all of Africa, in Uganda, and that is an early, Phase I trial to test safety.
Only one large-scale Phase III trial has begun.
VaxGen, Inc., a California company that has received federal funding, is testing a genetically engineered AIDS vaccine in 5,000 gay American men and 2,500 intravenous drug users in Bangkok, Thailand. All subjects should be recruited by later this year, with the first results available by late 2000.
A vaccine ready for large-scale use will not be ready for several years after that, even in the best case, said Dr. Don Francis, president of VaxGen and a former top AIDS researcher at the federal Centers for Disease Control and Prevention.
Something to contribute
One volunteer who has received his first inoculation with the VaxGen vaccine is John Bunting, 55, a program specialist at the Baltimore Department of Social Services.
"Sure, I had some worries. I'm human," said Bunting.
Workers at Johns Hopkins' Center for Immunization Research reassured him, and he took the plunge.
"I've lost dozens of friends to AIDS, and this is something very personal I can contribute," Bunting said.
But suspicion that a vaccine will do more harm than good is widespread, particularly among African-Americans, said Eric Zimmerman, who coordinates the AIDS trials at the Hopkins center, which enrolled its 524th vaccine volunteer yesterday.
That is true even though black Americans suffer from AIDS at a far higher rate than whites.
As a result of such infamous cases as the Tuskegee experiment, in which black men who believed they were being treated for syphilis were actually deprived of treatment, "there's an incredible amount of suspicion out there," Zimmerman said.
"I speak at black churches all the time, and I always ask, `If there were an AIDS vaccine available today, who would get it?' Rarely does anyone raise his hand," he said.
"We have to educate people so that when there is a vaccine, they'll be willing to take it."
For information about AIDS vaccine trials, call the Johns Hopkins Center for Immunization Research at 410-955-7283.
Pub Date: 5/19/99