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The World Health Organization says the data collected last year found 9.3 million cases - new cases - of tuberculosis. And the number of people who died from that disease is like the casualty list from some catastrophic war. New strains of TB are more resistant to available drugs than ever before, so scientists are reexamining a century-old vaccine to see if they can make it work better. NPR's Brenda Wilson reports.
BRENDA WILSON: In the pristine corridors of Aeras Global TB Vaccine Foundation in Rockville, Maryland, with its double-locked doors and self-contained water purification system, new TB vaccines are at various stages of development, set to be tested in people soon. Plant manager David MacCallum(ph) wants us to put on lab coats before we enter the area where the vaccines will be manufactured.
Mr. DAVID MACCALLUM (Plant Manager): So I'm going to ask you to don this garment here, 'cause we're going to go through the labs, and I'm going to ask you to wear safety glasses.
WILSON: That not only protects people from harm, it protects the vaccines from contamination. Aeras director Jerry Sadoff says the vaccines being developed here work on the same principle as vaccines have for hundreds of years.
Mr. JERRY SADOFF (Aeras Director): The basic idea of a vaccine is to fool the body into thinking it's infected so it can make an immune response and it's not really infected. And then it remembers that, so that later when it sees the real pathogen like TB or HIV or whatever, it recognizes that it's been infected before and it has a big immune response ready to go.
WILSON: But here at Aeras, Jerry Sadoff says modern science, molecular biology, immunology, and genetics is helping create a better TB vaccine using an existing TB vaccine called BCG and improving it.
Mr. SADOFF: We force the BCG to make a lot more of these pieces of itself we call antigens that come from all different parts of its life cycle so that it makes them all at once, so that we've made it into a super BCG, so to speak, telling the immune system that this is what I'm going to be like at all different stages of the TB lifecycle.
WILSON: The old BCG vaccine originated a hundred years ago when two French scientists isolated the TB bacilli in cows. Dr. Barry Bloom of the Harvard School of Public Health says that at the time, nearly a third of the population of Paris was dying of TB contracted from cow's milk.
Dr. BARRY BLOOM (Harvard School of Public Health): The experience in Paris was that bovine TB that people got by drinking milk was much more virulent in humans than TB that one caught from other patients. And as a small aside, that's what pasteurization has prevented in modern times. We heat milk and kill the bacillus.
WILSON: It took the French scientists 13 years of testing in rats, mice, and monkeys to turn the deadly cow bacillus into a form that was safe enough to test in humans. And then they gave it to one child whose mother had died of TB.
Dr. BLOOM: This child lived a long and healthy life, whereas someone who had a parent with TB at that time, about 30 percent would die of tuberculosis.
WILSON: The old BCG vaccine is still one of the most widely used vaccines in the world, but while it confers some protection on infants and children, it doesn't work very well in all populations. One strain provided as much as 85 percent protection in England and zero protection in India.
There's speculation that other bacteria closely related to TB and the environment and warm climates weaken the effectiveness of BCG. Some people may be more susceptible to tuberculosis for genetic reasons or because of poor nutrition. The list goes on. Jerry Sadoff at Aeras says they have a series of vaccines under development now that they are hoping will provide lifelong protection.
Mr. SADOFF: We have a regimen for infants and children so that we can protect infants from getting disease when they live in these very tight quarters where adults that have TB are coughing on them and spreading the disease. And then we think we'll have to have a booster regimen like you do for many other vaccines in the adolescent or young adult times.
WILSON: Human tests of Aeras vaccines are scheduled for sometime this year in South Africa, Kenya, India, and other countries with high levels of tuberculosis.
Brenda Wilson, NPR News.
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