Vaccine patch protects against anthrax, in mice

Immunization through the skin, using a patch, protects mice against normally lethal inhaled doses of anthrax bacteria, according to a new report.

Patch vaccination appears to be as safe as traditional injection methods, and just as effective in producing immunity, Dr. Richard T. Kenney from IOMAI in Gaithersburg, Maryland, told AMN Health.

"We are in the middle of the first clinical trial, although we do not yet have results," he added.

Kenney and colleagues vaccinated mice and rabbits with "recombinant protective antigen" (rPA) derived from Bacillus anthracis, the anthrax organism, and measured animals' responses.

The antibody response to patch vaccination was equivalent to that seen after intramuscular administration, the researchers report in the Journal of Infectious Diseases

All mice that were given rPA, whether by patch or injection, survived after a challenge with anthrax to the lungs, five weeks after the last vaccination. There were no survivors among unvaccinated mice.

The results confirm that a "formulated adhesive anthrax vaccine patch could deliver rPA to the epidermis to elicit robust and functional rPA responses," the team concludes.

They are also using this approach for other vaccines. "We currently have clinical programs in influenza, anthrax and a traveler's diarrhea vaccine and an expanding pipeline in various stages of preclinical development," Kenney commented.

"We have now dosed over 1500 people in various studies with more than 2500 vaccinations ... and have no indication that there are significant safety concerns."

SOURCE: Journal of Infectious Diseases, August 15, 2004.