Microneedle skin patches as effective as hypodermic needles for flu vaccination

Flu vaccine delivered through skin patches containing microneedles has proven at least as effective at preventing influenza in mice as intramuscular, hypodermic flu immunization. A team of researchers at Georgia Institute of Technology and Emory University believes the new microneedle skin patch method of delivering flu vaccine could improve overall seasonal and pandemic vaccination coverage in people because of stronger immune responses, decreased pain, increased convenience, lower cost, and simpler logistics over conventional hypodermic immunization.

The patches used in the experiments contained an array of stainless steel microneedles coated with inactivated influenza virus. The patches were pressed manually into the skin and after a few minutes, the vaccine coating dissolved off within the skin. The coated microneedle immunizations were compared to conventional intramuscular hypodermic injections at the same dose in another group of mice.

The researchers found that the microneedle vaccinations induced strong immune responses against influenza virus that were comparable to immune responses induced by the intramuscular, hypodermic immunizations. One month after vaccination, the researchers infected both groups of mice with a high dose of influenza virus. While all mice in a control group of unvaccinated mice died of influenza, all mice in both the hypodermic and the microneedle groups survived.

"Our findings show that microneedle patches are at least as effective at protecting against influenza as conventional hypodermic immunizations," says Mark Prausnitz, PhD, professor in the Georgia Tech School of Chemical and Biomolecular Engineering and senior author of the study. "Unlike conventional hypodermic injections, microneedles are prepared in a patch for simple administration, possibly by patients themselves, and inserted painlessly onto the skin without specialized training."