lished, and heard from representatives of DoD, FDA, and other federal agencies; from the vaccine manufacturer BioPort; from researchers studying the efficacy and safety of the vaccine; and from service members and others with concerns about the safety or efficacy of the vaccine. After the bioterrorism of fall 2001, the committee accelerated its original timetable for its review.

As indicated by evidence from studies in both humans and animals, the committee concluded that AVA, as licensed, is an effective vaccine to protect humans against anthrax, including inhalational anthrax. Moreover, because the vaccine exerts its protection via an antigen crucial to the action of the bacterium’s toxins, AVA should be effective against anthrax toxicity from all known strains of B. anthracis, as well as from any potential bioengineered strains.

After examining data from numerous case reports and especially epidemiologic studies, the committee also concluded that AVA is reasonably safe. Within hours or days following vaccination, it is fairly common for recipients to experience some local events (e.g., redness, itching, swelling, or tenderness at the injection site), while a smaller number of vaccine recipients experience some systemic events (e.g., fever and malaise). But these immediate reactions, and the rates at which they occur, are comparable to those observed with other vaccines regularly administered to adults. The committee found no evidence that vaccine recipients face an increased risk of experiencing life-threatening or permanently disabling adverse events immediately after receiving AVA, when compared with the general population. Nor did it find any convincing evidence that vaccine recipients face elevated risk of developing adverse health effects over the longer term, although data are limited in this regard (as they are for all vaccines).

Regarding manufacture of AVA, the committee reviewed and evaluated the steps taken by BioPort to win FDA approval of its production process. With the newly validated manufacturing process being used in a renovated facility, AVA will be produced under strict controls according to current FDA requirements. The newly produced vaccine is expected to have greater assurance of consistency than the vaccine produced at the time of its original licensure.

It remains important to continue and improve monitoring efforts to detect any adverse health effects caused by AVA and other vaccines. Also needed are studies to establish a quantitative correlation of protective levels of antibodies in animals with antibody levels in humans after full immunization. Direct tests of the efficacy of AVA are neither feasible nor ethical in humans. However, corre-



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