One day your annual flu shot could come in the mail. At least that's the hope of researchers developing a new method of vaccine delivery that people could even use at home: a patch with microneedles. Microneedles? That's right, tiny little needles so small you don't even feel them. Attached to a patch like a Band-Aid, the little needles barely penetrate the skin before they dissolve and release their vaccine. Researchers led by Mark Prausnitz of Georgia Institute of Technology reported their research on microneedles in Sunday's edition of Nature Medicine. The business side of the patch feels like fine sandpaper, he said. In tests of microneedles without vaccine, people rated the discomfort at one-tenth to one-twentieth that of getting a standard injection, he said. Nearly everyone said it was painless. Some medications are already delivered by patches, such as nicotine patches for people trying to quit smoking. That's simply absorbed through the skin. But attempts to develop patches with the flu vaccine absorbed through the skin have not been successful so far. In the Georgia Tech work, the vaccine is still injected. But the needles are so small that they don't hurt and it doesn't take any special training to use this kind of patch. By developing needles that dissolve, there are no leftover sharp needles, especially important for people who might give themselves the vaccine at home, he said. The patch, which has been tested on mice, was developed in collaboration by researchers at Georgia Tech and Emory University, Prausnitz said. The researchers are now seeking funds to begin tests in people and, if all goes well, the patch could be in use in five years, he said. The patch is placed on the skin and left for 5 minutes to 15 minutes, he said. It can remain longer without doing any damage, he said. The little needles are 650 microns (three-hundredths of an inch) in length and there are 100 on the patch used in the mouse study.
