In 2007, researchers from Emory University and the Georgia Institute of Technology began developing a new vaccine patch technology containing an array of stainless steel microneedles coated with inactive influenza virus. The effectiveness of the patch to prevent influenza was recently tested on mice. In the experiments, the investigators manually pressed the patch into the rodents' skin. The vaccine coating dissolved within just a few minutes. Another group of mice received the same dose of the vaccine through traditional intramuscular hypodermic injections, while a control group was left unvaccinated.

A month following the vaccination, the mice were infected with a high dose of the active virus. All of the mice in the control group died, while all mice that received the vaccination - either through the microneedle patch or through hypodermic injections - survived. "Our findings show that microneedle patches are just as effective at protecting against influenza as conventional hypodermic immunizations," says Richard Compans, Ph.D., Emory professor of microbiology and immunology and one of the paper's senior authors. "In addition, vaccine delivery into the skin is desirable because of the skin's rich immune network." Dr. Compans and his colleagues published their findings in a recent online edition of the journal, Proceedings of the National Academy of Sciences.

In addition to protection from influenza, the patches offer other benefits that could help enhance overall seasonal vaccination coverage. Unlike conventional hypodermic injections, the patches are painless to insert and require no special training. As a result, patients may be able to administer the patches themselves. In addition, says Mark Prausnitz, Ph.D., professor in the Georgia Tech School of Chemical and Biomolecular Engineering and co-senior author, "These micron-scale needles can be mass produced using low-cost methods for distribution to doctors' offices, pharmacies and, possibly, people's homes."

A potential lower dosage requirement is another important advantage, particularly in light of the recent H1N1 virus scare. The capacity to manufacture adequate supplies of seasonal vaccines is often limited, and a future influenza pandemic would place even greater strain on vaccine availability. Moreover, the microneedle patch delivery system requires less storage and is easier to transport - it can be placed in an envelope for delivery by the postal service, for example - making it an attractive alternative for use in developing countries.

Before studies can be conducted on humans, the researchers are planning to conduct additional immunization studies on other animal models, including guinea pigs or ferrets. The minimum vaccine dose required for full protection also needs to be determined.

News Release: Vaccine given with microneedle patches proves effective  www.newswise.com   April 27, 2009