Let's face it, most of us do not enjoy getting shots. The importance of immunizations, however, requires that many, if not all of us need to make the trip to the doctor's office for an occasional injection of medicine or vaccines.

That, however, may one day change. Researchers have developed a patch delivery system embedded with hundreds of microscopic needles that are painless and eventually dissolve into the skin. The patch would allow for self-immunization and is believed to better at administrating vaccines than needles.

The benefits would also extend to large-scale public health initiatives, particularly in developing countries and during pandemics, while also eliminating the hazards of handling and disposing of dirty needles. Once the needles on the patch dissolve, the patch can be safely discarded because it no longer has any sharp materials.

The research was supported by the National Institutes of Health (NIH) and is published in the journal Nature Medicine. The vaccine patch contains an array of 100 tiny needles (650 microns in length) that penetrate the skin and then dissolve. Initial results suggest that the patch provides improved immunity to influenza when compared to conventional needles. The skin was determined to be an ideal target to deliver the vaccine because it is rich in cells that are involved in the immune response.

The development of the patch first went through tests in animal models. Researchers divided the animals into three groups: one group received influenza vaccine by intramuscular injection with a needle; another group received influenza vaccine by way of the patch; and a third group received a patch with no vaccine (control). All three groups were then exposed to influenza virus 30 days later.

What they observed was that both groups that had been vaccinated remained healthy, while the control group mice contracted the flu and died as a result. Three months later, the animals were again exposed to the influenza virus, and the group that was immunized with the patch appeared to fare better. In fact, they seemed to able to clear the virus more effectively than the group vaccinated with the a conventional needle, suggesting a better "recall" response to the immunization.

The patch method also has the added advantage of being in a dry formulation, which means that it does not require refrigeration and is more stable over time, especially during distribution and storage. This could be a significant development in areas where poor medical facilities require the re-use of hypodermic needles, which can increase the likelihood that diseases such as HIV and hepatitis will be spread. The patches also require a minimal amount of training to use.

Though the patches were initially designed to administer influenza vaccines, researchers envision that they will one day be used for a variety of immunizations. With the current cost of production equivalent to the conventional needle and syringe, the patch could be even more economical in the end because of lower personnel and disposal costs.