Anthrax vaccine antibodies could provide cross-species survival prediction

Vaccine-induced antibodies from the anthrax vaccine could provide an effective cross-species prediction of survival from a biological attack, according to a recent study.

Researchers with the Biostatistics Research Branch of the National Institute of Allergy and Infectious Diseases examined data from animal studies to determine if a bridge existed to predict inhalation anthrax survival in humans. Clinical trials to assess vaccine efficacy for anthrax may not be conducted on humans, so animal trials are used to establish viable countermeasures.

"We examined data from 21 of those studies to determine whether an immunological bridge based on lethal toxin neutralization activity assay can predict survival against an inhalation anthrax challenge within and across species and genera," the researchers said. "The 21 studies were classified into 11 different settings, each of which had the same animal species, vaccine type and formulation, vaccination schedule, time of TNA measurement, and challenge time."

The team determined that the TNA assay predicted 78.6 percent survival in rhesus macaques, not far off from the actual survival rate of 83.0 percent. The TNA assay predicted 72.6 percent in rabbits with an actual survival rate of 64.6 percent.

"These data add support for the use of TNA as an immunological bridge between species to extrapolate data in animals to predict anthrax vaccine effectiveness in humans," the researchers said.