The safety of multi-dose vials in allergy immunotherapy.

Objective: To prospectively evaluate the risks of vial contamination after routine clinical use of multiple-dose vials for immunotherapy.

Study Design: Prospective observational study of immunotherapy vial cultures from June 2007 to January 2008.

Setting: Tertiary care outpatient otolaryngology clinic.

Results: Over an 8-month period, 136 consecutive vials were cultured for aerobic and anaerobic bacteria at the 3-month expiration date after regular use in an outpatient allergy clinic and dispensation of multiple doses of injection immunotherapy from each vial. All vials had negative cultures.

Conclusion: Immunotherapy vials are at low risk to undergo contamination in routine use. Important factors include aseptic technique, bacteriostatic agents, and expiration dating.