Vaccine Patch Could Eliminate Needles
Do you hate needles? Most people do, but soon you may be able to get a flu vaccine or other vaccinations through a patch rather than an injection. Details about use of a vaccine patch in mice were published in the journal Nature Medicine.
According to Mark Prausnitz, a professor in the Georgia Tech School of Chemical and Biomolecular Engineering, “in this study, we have shown that a dissolving microneedle patch can vaccinate against influenza at least as well, and probably better than, a traditional hypodermic needle.” The study was conducted by scientists from Emory University and the Georgia Institute of Technology.
The vaccine patch is composed of hundreds of microscopic needles that dissolve when placed on the skin. This approach provides several important benefits, not least of which is allowing vaccines to be self-administered or given out by individuals without medical training. It also eliminates hypodermic needles and safety concerns about disposal of “sharps.” The best part for vaccine recipients is that the patch is painless.
The availability of such vaccine patches during a pandemic and large-scale immunization programs could greatly simplify and streamline the distribution of vaccines, especially in developing nations. Prausnitz also noted that the vaccine patch could also “simplify vaccine programs in schools and assisted living facilities.” Yet another advantage is the elimination of the re-use of hypodermic needles, which occurs in many poor parts of the world. Re-use of needles contributes to the spread of HIV, hepatitis B, and other diseases.
The scientists tested the vaccine patch in mice. One group of mice received the flu vaccine via the traditional hypodermic needle, while another group received the vaccine through the dissolving microneedles in the patch. A control group was given a microneedle patch that did not contain the vaccine. Thirty days later, all the mice were infected with influenza virus. The mice in the treated groups remained healthy while the unvaccinated mice died.
Three months after the vaccination, the scientists exposed a different group of immunized mice to flu virus and found that those who had received the vaccine patch were better able to eliminate the virus from their lungs than those that had received the vaccine with a hypodermic needle.
The vaccine patch works when it is pressed into the skin, which triggers the microneedles to rapidly dissolve in bodily fluids. This leaves behind the water-soluble backing, which can be thrown away safely because it does not contain any sharps. The vaccine is freeze-dried and mixed with another material before being placed into the microneedle molds. The patch is then sealed (polymerized) at room temperature using ultraviolet light.
Although this study evaluated the use of the microneedle patch with the flu vaccine, the approach should be useful for other immunizations as well. The authors note that the mass production of microneedle patches is expected to cost about the same as conventional hypodermic needle techniques and could reduce overall costs related to immunization programs because medical personnel are not needed and safe disposal of sharps is eliminated.
The microneedle vaccine patch will likely not be ready for next flu season, as clinical trials are necessary to ensure safety and effectiveness. Other vaccine delivery techniques may also be studied, hopefully someday offering individuals better, safer protection against a wide variety of diseases—without needles.
Georgia Institute of Technology