POSTEXPOSURE PROPHYLAXIS AGAINST EXPERIMENTAL INHALATION ANTHRAX

Inhalation anthrax is a rare disease that is almost invariably fatal. This study determined whether a prolonged course of postexposure antib iotics with or without vaccination would protect monkeys exposed to a lethal aerosol dose of Bacillus anthracis when the antibiotic was disc ontinued. Beginning 1 day after exposure, groups of 10 animals were gi ven penicillin, ciprofloxacin, doxycycline, doxycycline plus vaccinati on, vaccination alone, or saline. Antibiotics were administered for 30 days and then discontinued. Vaccine was given on days 1 and 15. Two a nimals died of causes other than anthrax and were not included in the statistical analysis. Nine of 10 controls and 8 of 10 animals given on ly vaccine died. Each antibiotic regimen completely protected animals while on therapy and provided significant long-term protection upon di scontinuance of the drug (penicillin, 7 of 10 survived, P < .02; cipro floxacin, 8 of 9 survived, P < .002; doxycycline, 9 of 10 survived, P < .002; doxycycline plus vaccination, 9 of 9 survived, P < .0002). Pro tection against rechallenge was provided by combining postexposure ant ibiotic treatment with vaccination.