Clinical immunogenicity of measles, mumps and rubella vaccine delivered by the Injex jet injector: comparison with standard syringe injection.

Background The measles, mumps and rubella (MMR) vaccine confers trivalent immunity in >90% of subjects immunized. Alternatives to the use of needles for vaccine administration have recently been made available. We report the safety and efficacy of MMR vaccine delivered by a new needle-free jet injector (Injex) compared with needle syringe administration. Methods. Forty adolescent subjects were injected bilaterally via needle syringe and jet injector with MMR vaccine and reconstitution buffer. Subjects were blinded as to which device contained the vaccine. Subjects were followed longitudinally for 12 weeks postimmunization, and titers to measles, mumps and rubella immunogens were determined by enzyme immunoassays, Injection pain was quantified using the visual analog pain scale, Results. Adverse events were mild and included injection site soreness (jet injector, 2.5% of subjects; needle, 12.5%), injection site bleeding (jet injector, 0%; needle, 7.5%), malaise (jet injector, 0%; needle, 5%) and fever (jet injector, 0%; needle, 2.5%), All subjects displayed measles titers significantly above baseline during the follow-up, Ninety-five percent of subjects displayed titers above baseline for the mumps antigen vs. 97.5% for rubella, No significant differences in immunogenicity were found between groups receiving the vaccine via the jet injector or the needle syringe at any time during the follow-up (P > 0.05), Injection pain scores were not significantly different between injector types (P > 0.05), Conclusions. We conclude that the measles, mumps and rubella vaccine can be safely and effectively delivered by the Injex jet injector, This device therefore provides an alternative to standard needle injection and a methodology that might reduce the risk of needle stick accidents.