Team Readies TB Vaccine Booster for Human Tests

Seattle scientists have developed an experimental booster vaccine that could extend the efficacy of the Bacille Calmette-Guérin (BCG) vaccine. BCG vaccine is administered in many countries where TB prevalence is high in order to prevent serious forms of TB in children; however, its effectiveness wears off between ages 10 and 15.

In September, scientists reported progress with a vaccine based on four TB proteins and an adjuvant. The 15-year research project was led by the non-profit Infectious Disease Research Institute (IDRI).

"The thing that got me excited is that this is the first example I know of where a boost strategy really made a substantial difference in outcome," said David Sherman, a TB expert at Seattle BioMed, who was not involved in the project.

"If we think about making a dramatic reduction in tuberculosis death and transmission, a vaccine will be a very important component," said study co-author Steven Reed, founder and director of IDRI. The National Institutes of Health funded the research.

In eight BCG-vaccinated guinea pigs, the vaccine candidate was able to protect the animals throughout their life span. The vaccine also protected mice and induced a strong immune response in monkeys.

Reed hopes to begin human trials early next year. Even if these prove successful, however, it could be 10 years before the booster reaches the market, Reed said. A BCG booster might be given to children when they first enter school, he said.

The study, "A Defined Tuberculosis Vaccine Candidate Boosts BCG and Protects Against Multidrug-Resistant Mycobacterium tuberculosis," was published in Science Translational Medicine (2010;2(53):53ra74).

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