Blood test could predict effectiveness of anthrax vaccines

Researchers recently determined that a sensitive, blood-based assay that measures vaccine-induced antibodies to anthrax in animals could detect a reliably measured protective response in multiple species, according to a recent study.

Scientists with the National Institute of Allergy and Infectious Diseases and the Centers for Disease Control and Prevention published a study in the September 12 issue of Science Translational Medicine that suggests the assay could serve as a predictor for how well anthrax vaccines might work in humans. The assay would be useful because anthrax vaccine studies in humans are not ethical or safe to conduct.

The Animal Rule, a regulation adopted in 2002 by the U.S. Food and Drug Administration, provides FDA drug approval based on countermeasure effectiveness data in animals combined with immune response and safety data in humans. This rule allows for the study and approval of vaccines that cannot be ethically or feasibly tested in humans.

The researchers looked at 21 previous anthrax vaccine studies and determined that the lethal toxin neutralization activity assay shows if protective antibodies are formed from an anthrax vaccine. After comparing TNA results with actual survival rates in the studies, the scientists found TNA could serve as an immunological bridge between species to predict anthrax vaccine effectiveness in humans using animal data.

The research team said the approach could be used to make more effective anthrax vaccines and to use them in the safest way possible. The TNA method could also be used to develop, test and optimize vaccines against other diseases as well.