A randomized controlled study to assess the immunogenicity and tolerability of a 2012 trivalent seasonal inactivated influenza vaccine administered via a disposable syringe jet injector device versus a traditional pre-filled syringe and needle

The Stratis® disposable syringe jet injection (DSJI) system (PharmaJet Inc., Denver, USA) delivers vaccine utilizing a spring powered energy source to create a fine high-velocity jet of liquid that directly penetrates the skin without using a needle. We performed a study to collect data on the effect of the Stratis DSJI device on influenza immunization in 46 predominantly elderly subjects (28M, 18F; mean age 61 years) who were randomized 1:1 to receive Fluvax 2012 trivalent inactivated influenza vaccine via prefilled N-S or Stratis DSJI. H1N1 seroprotection was not significantly different for vaccine delivered by DSJI (86.4%, 95% CI 72.1-100) or N-S (79.2%, 95% CI 63.0-95.4), and likewise for H3N2 and B strains. The DSJI had a ∼2-fold higher mean injection pain score (DSJI: 3.0 versus N-S 1.58, p = 0.045) plus increased rates of swelling and tenderness but this was offset by a lower rate of elicited systemic reactions, particularly the frequency of post-immunization headaches (DSJI: 9% vs N-S: 33.3%). This study suggests that subject to confirmation of non-inferiority in an appropriately powered study, the Stratis DSJI is a viable alternative strategy for the administration of seasonal influenza vaccines with particular appeal for individuals with needle phobia. Australia New Zealand Clinical Trials Register: ACTRN12612000709842.