Medical Responses to Small-Scale Bioterrorism-Related Anthrax Attacks: A Cost-Effectiveness Analysis

Parada JP, Schmitt BP, Dobrez D, Kyriacou DN, Golub RM, Bennett CL. Medical Responses to Small-Scale Bioterrorism-Related Anthrax Attacks: A Cost-Effectiveness Analysis. Poster session presented at: VA HSR&D National Meeting; 2006 Feb 1; Arlington, VA.

Related HSR&D Project(s)

• IIR 02-080 – Bioterrorism: Cost-Effectiveness of Medical Responses

Objectives:Although large-scale bioterrorism-related anthrax attacks are plausible, small-scale attacks directed at governmental offices, postal service buildings, media organizations, or commercial areas are more likely. Limiting the effects of small-scale anthrax attacks requires timely and effective intervention strategies that may differ from large-scale attacks. We sought to measure the cost-effectiveness of medical responses to such an attack.Methods:Cost-effectiveness analyses were conducted to evaluate a simulated small-scale anthrax attack directed against a postal distribution center. The following response strategies were compared: (1) pre-attack vaccination of high-risk personnel; (2) post-attack antibiotic treatment followed by vaccination of exposed personnel; and (3) post-attack antibiotic treatment without vaccination of exposed personnel. We constructed Markov models to evaluate potential attacks over a ten-year period. Sensitivity analyses were conducted by varying model parameters. Results are expressed as cost per additional quality adjusted life year (QALY) saved.Results:Post-attack strategies (antibiotic vaccination) for exposed postal workers are more cost-effective than pre-attack vaccination. Pre-attack vaccination of high-risk personnel does not become cost-effective until the cost per vaccination dose is unrealistically low ( = $0.30/dose) or the risk of exposure is three times greater than the base case. However, if post-attack vaccination, as theorized, accelerates anthrax toxicity in antibiotic non-adherent individuals, then post-attack antibiotics alone would be the optimal strategy. Prolonged antibiotic therapy (4 months) does not change the optimal strategy. The cost-effectiveness advantage of post-attack antibiotic plus vaccination is clear but small as compared to antibiotics alone.Implications:Cost-effective strategies for responding to a small-scale anthrax attack against a postal facility depend on base case assumptions of infection rates and vaccination costs. Post-attack antibiotic treatment and vaccination is the optimal response strategy for most situations. Impacts:Our study informs administrators and policy makers on the cost-effectiveness of various medical responses to a small-scale anthrax attack directed at a government building, using a postal facility as our model target. Although post-attack combination therapy of antibiotics + vaccination is the optimal response strategy for most situations, we speculate that the reluctance of many individuals to receiving anthrax immunization and the limited advantage of additional vaccination over post-exposure antibiotics alone may tempt administrators and policy makers to defend the use of antibiotics alone as a reasonable response strategy.