Vaccines for preventing anthrax.

BACKGROUND

Anthrax is an acute bacterial skin disease which may be fatal. Three anthrax vaccines are commercially available but their comparative effectiveness and safety is not clear.

OBJECTIVES

The objective of this review was to assess the effects of human anthrax vaccines in healthy adults and children.

SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, Medline, Embase and the reference lists of articles. We handsearched the journal Vaccine and contacted researchers in the field.

SELECTION CRITERIA: Randomised and quasi-randomised trials comparing anthrax vaccines with placebo, vaccines for other diseases or no intervention.

DATA COLLECTION AND ANALYSIS: Trial quality assessment and data extraction was conducted independently by the six authors.

MAIN

RESULTS

Two trials involving 16,052 people were included. Both trials had methodological limitations. Compared to placebo, vaccination was associated with a reduced risk of contracting anthrax (relative risk 0.16, 95% confidence interval 0.07 to 0.35). Compared to placebo, the killed vaccine was associated with a higher incidence and severity of adverse effects (odds ratio 5.15, 95% confidence interval 2.28 to 11.61). Just over 5% of participants in the vaccine group reported adverse effects. The effectiveness of the vaccine does not appear to be influenced by the route of inoculation.

REVIEWER'S

CONCLUSIONS

Killed anthrax vaccines appear to be effective in reducing the risk of contracting anthrax with a relatively low rate of adverse effects. Further research should be restricted to testing new vaccines only.