A Band-Aid-like patch does away with big, scary needles and could be available over-the-counter.
The patch replaces one large needle with 100 tiny dissolvable ones on a patch.
Once the microneedles pierce the skin, they dissolve and the vaccine enters the blood stream.
The invention has been tested on mice with effective results.
For most people, the worst thing about getting a vaccination is the big, scary hypodermic needle. So researchers have invented a new vaccine-delivery system that replaces the large single needle with 100 tiny dissolvable ones embedded in a Band-Aid-like patch.
The new patch can immunize mice against influenza just as effectively as conventional needle vaccination, its developers report online July 18 in Nature Medicine.
The new patch is coated with 100 microneedles that are shorter than a nickel's thickness. Lead study author Sean Sullivan, who conducted the research while at the Georgia Institute of Technology in Atlanta, likens the patch to a Band-Aid with a bunch of tiny needles sticking out on the sticky side.
Once the microneedles pierce the skin, they dissolve into the surrounding bodily fluid, releasing the vaccine in the process. The whole thing takes anywhere from 30 seconds to five minutes, Sullivan says.
Since the patch just needs to be slapped on and can be stored at room temperature, medical training and careful handling aren't required. People could pick up the patches from the pharmacy or even get them in the mail and vaccinate themselves, says Sullivan, who now works for medical device manufacturer Becton, Dickinson and Company.
The researchers say that the patch could be used to replace a number of needle vaccinations, including the annual flu shot.
"This is an attractive approach," says vaccinologist Kathryn Edwards of Vanderbilt University in Nashville, who was not involved in the study. But she adds that more studies are needed before this method could be adopted for humans.
"As we know, mice are not men. Whether this would be equally effective in humans as in mice is obviously a question that needs to be investigated."
The new patch might actually be more effective than shots at generating an immune response, the researchers say. Standard vaccines are injected into muscles, but "there really are no immune cells in there," Sullivan says. The vaccine has to find its way from the muscle to the blood and lymph system to encounter the cells that spur protection.
With the microneedle patch, the vaccine is delivered into the immune-cell-rich skin. A number of studies have shown that skin-based delivery of vaccines is more effective than injections into muscle, says study coauthor Mark Prausnitz of Georgia Tech. Because of this stronger response, the patch might make it possible to get equal protection with lower doses of vaccine.
Physician Wilbur Chen of the Center for Vaccine Development at the University of Maryland School of Medicine in Baltimore says the new patch "might prove a powerful public health tool." Chen points out that the patch might be especially helpful in developing countries, where electricity to keep liquid vaccines cold is in short supply, and needles and trained medical personnel are scarce.
The team hasn't conducted studies to see how long the patches can sit at room temperature, but Sullivan predicts that they would be stable on the order of months.
Prausnitz says that the cost of the microneedle patch would be similar to current needle-based vaccines. He adds that the technology is ready for clinical trials, which he anticipates in the next couple of years.