Short-course postexposure antibiotic prophylaxis combined with vaccination protects against experimental inhalation anthrax

Nicholas J. Vietri, Bret K. Purcell, James V. Lawler, Elizabeth K. Leffel, Pedro Rico, Christopher S. Gamble, Nancy A. Twenhafel, Bruce E. Ivins, Henry S. Heine, Ryan Sheeler, Mary E. Wright, Arthur M. Friedlander

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


Prevention of inhalational anthrax after Bacillus anthracis spore exposure requires a prolonged course of antibiotic prophylaxis. In response to the 2001 anthrax attack in the United States, ≈ 10,000 people were offered 60 days of antibiotic prophylaxis to prevent inhalational anthrax, but adherence to this regimen was poor. We sought to determine whether a short course of antibiotic prophylaxis after exposure could protect non-human primates from a high-dose spore challenge if vaccination was combined with antibiotics. Two groups of 10 rhesus macaques were exposed to ≈ 1,600 LD50 of spores by aerosol. Both groups were given ciprofloxacin by orogastric tube twice daily for 14 days, beginning 1-2 h after exposure. One group also received three doses of the licensed human anthrax vaccine (anthrax vaccine adsorbed) after exposure. In the ciprofloxacin-only group, four of nine monkeys (44%) survived the challenge. In contrast, all 10 monkeys that received 14 days of antibiotic plus anthrax vaccine adsorbed survived (P = 0.011). Thus postexposure vaccination enhanced the protection afforded by 14 days of antibiotic prophylaxis alone and completely protected animals against inhalational anthrax. These data provide evidence that postexposure vaccination can shorten the duration of antibiotic prophylaxis required to protect against inhalational anthrax and may impact public health management of a bioterrorism event.

Original languageEnglish (US)
Pages (from-to)7813-7816
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number20
StatePublished - May 16 2006
Externally publishedYes


  • Bacillus anthracis
  • Treatment
  • Vaccine

ASJC Scopus subject areas

  • General


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