Rationale:

• Preexposure vaccination protects against cutaneous and inhalational anthrax.
• Anthrax vaccine is safe, but side effects include local reactions, fever, chills, and body aches.

Evidence:

• Animal and human studies support the efficacy of anthrax vaccine for prevention of inhalational and cutaneous anthrax (1; 2; 3; 4; 5; 6).
• The basis for the six initial vaccine doses followed by yearly boosters is not well defined (7).
• Mild cutaneous reactions occur in 20% of patients vaccinated, whereas severe local reactions and systemic reactions occur in 1% (1; 8; 9).
• Although no adverse birth outcomes occurred in a recent study, the evidence for use of anthrax vaccine in pregnancy is not conclusive (8; 10).
• Contraindications to anthrax vaccine include history of anthrax infection or anaphylaxis to a previous dose of anthrax vaccine (8).
• There was no evidence for an unusual rate of any severe adverse event or other medically important adverse events in more than 500,000 military personnel vaccinated against anthrax (11).
• A study of U.S. Army personnel who received 1 dose of AVA between March 1998 and February 2002 showed that this group had no greater risk of disability than those who had not received AVA (12).
• Assessment of the first 1005 subjects enrolled in a multisite, randomized, double-blind, noninferiority, phase 4 human clinical trial of AVA showed that subjects who received three or four intramuscular doses of AVA over 6 months had the same antibody responses at 7 months as those who received the standard schedule of four subcutaneous doses in the first 6 months. Intramuscular administration of AVA also resulted in fewer side effects at the injection site as compared to subcutaneous injection (13).

Comments:

• AVA (BioThrax®, Emergent BioSolutions) is the only licensed human vaccine for anthrax in the U.S.