UNC-CH, Harvard team up on inhaled TB vaccine

Scientists at UNC-Chapel Hill and Harvard University have developed a novel inhaled tuberculosis vaccine that eliminates the need for refrigeration and water that has made the current vaccine problematic in some regions.

If the vaccine tests as well in humans as it has in animals, it could be a promising weapon against a disease that remains a scourge of the developing world.

"This is arguably the first step towards future potential vaccines that elicit greater immunity to tuberculosis," said Tony Hickey, a professor in the School of Pharmacy at the University of North Carolina at Chapel Hill.

The standard vaccine for tuberculosis, first used in people in 1921, must be refrigerated and then reconstituted in medical-grade water for injection. That hinders immunization efforts in some developing countries, where people often live far from medical facilities and have neither clean water nor electricity.

Tuberculosis is a respiratory illness that annually sickens 9 million people and kills up to 2 million, mostly in developing countries. In the United States, children and adults are not typically immunized against tuberculosis because the disease is not widespread here.

The UNC-CH/Harvard collaboration took the same type of vaccine used in injected tuberculosis immunizations and reformulated it as an extremely fine powder. Tests in guinea pigs treated with the inhaled vaccine and then subsequently exposed to tuberculosis showed that it protected the animals better than the conventional injected vaccine. The results were published this week in the Proceedings of the National Academy of Sciences.

Just 1 percent of lung and spleen tissue taken from animals vaccinated with the inhaled vaccine showed contamination with tuberculosis. About 5 percent of lung and 10 percent of spleen tissue taken from animals immunized with conventional injected vaccine were colonized with tuberculosis.

Hickey, an internationally recognized expert in dry powder aerosol delivery systems, such as those used to dispense Advair asthma medicine, conducted animals tests in his lab at UNC-CH. The dry powder vaccine was developed in the laboratory of David Edwards, a professor of biomedical engineering at Harvard University. The research was supported by a Grand Challenge Grant from the Bill and Melinda Gates Foundation, which has called on doctors and scientists to address the world's leading causes of disease.

Dr. Richard Frothingham, a vaccine expert at Duke University, praised the inhaled vaccine as a creative approach to finding more effective ways to target tuberculosis.

"There is a pressing need for a better tuberculosis vaccine," he said.

The next step for the UNC-CH-Harvard vaccine is to test its safety in humans and then conduct clinical trials. Hickey said plans are already in motion to test the vaccine as soon as next year in South Africa, where tuberculosis is highly prevalent.

In adults, the vaccine would be administered using a simple tube inhaler that looks like a plastic drinking straw, Hickey said. After piercing the tube, patients would breathe in while holding it in their mouth. Infants could receive the vaccine via a modified pacifier designed by the design company Manta Product Development, which worked with the research team.

"You can have the baby essentially suck on it and blow the powder into the back of the throat," Hickey said.