The first European approval application for a vaccine delivered via a new intradermal (ID) microinjection system developed by BD (Becton, Dickinson & Company) has been filed by Sanofi-Pasteur, the vaccines division of the Sanofi-Aventis group

The European Medicines Agency (EMEA) has accepted the submission for the first influenza vaccine to use the BD Soluvia system for review. In clinical trials involving more than 7,000 adult or elderly subjects, the ID vaccine triggered higher levels of seroprotective immune response against all tested influenza strains than standard intramuscular (IM) influenza vaccination.

With BD Soluvia, a prefillable microinjection system integrated with a thin needle only 1.5mm in length, the vaccine can be delivered accurately within the dermal layer of the skin. As BD pointed out, this layer contains a dense network of lymphatic vessels feeding local lymph nodes, which gives the vaccine rapid and efficient access to the immune system. The microneedle is attached to a glass syringe pre-filled with the vaccine dose and a needle-shielding system that covers the needle after injection.

BD has independently conducted clinical trials with BD Soluvia involving more than 700 subjects and 3,500 injections, to make sure the system is safe and easy to handle. In the trials conducted by Sanofi-Pasteur, ID delivery of the influenza vaccine using BD Soluvia was shown to be especially effective at enhancing the immune response in the elderly. The French company sees this as an important distinction, given that the immune system tends to weaken with age, making the elderly not only more susceptible to infection but less responsive to vaccination.

Despite the documented immunological and pharmacological advantages of ID vaccine delivery, the Mantoux technique is not commonly used due to difficulties in performing the procedure easily, reliably and effectively in a clinical setting, noted Laurent and colleagues in a paper published last October in the journal Vaccine . These difficulties include the need for training and practice as well as problems with inelastic skin or age-related changes that can hamper correct placement of the needle in the dermal layer. Moreover, dose inconsistency "is unavoidable due to inherent variability in on-site syringe filling and air bubble purging processes", the authors point out. The 'dead volume' of vaccine left in the vial and syringe after injection is a major source of wastage during the injection process.

Currently, only BCG and rabies vaccines are indicated for ID administration using the Mantoux technique.