Patches containing micron-scale needles that dissolve into the skin could simplify immunization programs by introducing self-administration and eliminating concerns over the use of hypodermic needles, their sharps disposal and re-use.

Mark Prausnitz and co-workers, Georgia Institute of Technology, USA, have used such patches to administer influenza vaccinations to mice. The vaccine delivered in this way provided complete protection and, compared to conventional intramuscular injection, resulted in more efficient lung virus clearance and enhanced cellular recall responses after challenge.

The microneedle arrays were made from poly-vinyl pyrrolidone, the monomer of which was mixed with the freeze-dried vaccine before being placed into microneedle molds and polymerized at room temperature using ultraviolet light.

• Dissolving polymer microneedle patches for influenza vaccination
  S. P Sullivan, D. G Koutsonanos, M. del Pilar Martin, J. W. Lee, V. Zarnitsyn et al.,
  Nat. Med. 2010, 16.
  DOI: 10.1038/nm.2182