Safety, tolerability, and immunogenicity of inactivated trivalent seasonal influenza vaccine administered with a needle-free disposable-syringe jet injector.

Background: Jet injectors (JIs) avoid safety drawbacks of needle-syringe (N-S) while generating similar immune responses. A new generation of disposable-syringe jet injectors (DSJIs) overcomes the cross-contamination risk of multi-use-nozzle devices used in 20th-century campaigns. In the first study in humans, the newly-US-licensed LectraJet (R) model M3 RA DSJI was compared to N-S. Methods: Sixty healthy adults received one 0.5 mL intramuscular dose of the 2009-2010 seasonal, trivalent, inactivated influenza vaccine (TIV) in randomized, double-masked fashion by either DSJI (n =30) or N-S (n = 30). Adverse reactions were monitored for 90 days after injection, and serologic responses assayed by hemagglutination inhibition (HI) at days 28 and 90. Results: There were no related serious adverse events (SAEs), nor differing rates of unsolicited AEs between DSJI and N-S. Solicited erythema and induration occurred more often after DSJI, but were transient and well-tolerated; a trend was noted for fewer systemic reactions by DSJI. Pre-vaccination HI geometric mean titers (GMT) increased by 28 days for H1N1, H3N2, and B antigens by 13-, 14-, and 8-fold via DSJI, and by 7-, 10-, and 7-fold for N-S, respectively. No trending differences in GMT, seroconversion, or seroprotection were noted; sample sizes precluded non-inferiority assessment. Conclusions: DSJI delivery of TIV is well-tolerated and immunogenic. (C) 2011 Elsevier Ltd. All rights reserved.