The new study, published in the journal Nature Medicine, details the usage of patches containing micron-scale needles, which carry vaccine with them as they dissolve into the skin. This simplifies immunization programs by eliminating the use of hypodermic needles and their “sharps” disposal and re-use concerns. Moreover, the new technique can be easily applied, thus allowing could self-administration of vaccine during pandemics. Other situations that might benefit from this development are large-scale immunization programs, usually common in developing nations.
The research, conducted by scientists from Emory University and the Georgia Institute of Technology, is the first to evaluate the immunization benefits of dissolving microneedles. Professor Mark Prausnitz from the Georgia Tech School of Chemical and Biomolecular Engineering, said that in this study the team has shown “that a dissolving microneedle patch can vaccinate against influenza at least as well, and probably better than, a traditional hypodermic needle.”
The experiments tested the technology on laboratory mice. The device is just 650 microns in length, and it’s assembled into an array of 100 needles; the design makes the microneedles dissolve when penetrating the outer layers of skin. The dissolving microneedles appear to provide improved immunity to influenza when compared to vaccination with hypodermic needles.
“The skin is a particularly attractive site for immunization because it contains an abundance of the types of cells that are important in generating immune responses to vaccines,” said Richard Compans, professor of microbiology and immunology at Emory University School of Medicine.
The study included three groups of mice. The first received the influenza vaccine using traditional hypodermic needles injecting into muscle; the second group received the vaccine through dissolving microneedles applied to the skin, and the third – a control group – had microneedle patches containing no vaccine applied to their skin. When infected with influenza virus 30 days later, the two groups that had received the vaccine remained healthy while mice in the control group contracted the disease and died.
The next phase took place three months after vaccination. The researchers exposed a fourth group of mice, also immunized to flu virus, and found that animals vaccinated with microneedles appeared to have a better “recall” response to the virus and thus were able to clear the virus from their lungs more effectively than those that received vaccine with hypodermic needles.
This is not the only benefit, says Ioanna Skountzou, an Emory University assistant professor. “Another advantage of these microneedles is that the vaccine is present as a dry formulation, which will enhance its stability during distribution and storage,” she said. “We envision people getting the patch in the mail or at a pharmacy and then self administering it at home,” adds Sean Sullivan, the study’s lead author from Georgia Tech. “Because the microneedles on the patch dissolve away into the skin, there would be no dangerous sharp needles left over.”
Developing countries could benefit greatly from this newly introduced technology. In places that suffer from poor medical infrastructure, sometimes patients and clinicians re-use hypodermic needles, contributing to the spread of diseases such as HIV and hepatitis B. Dissolving microneedle patches would eliminate re-use while allowing vaccination to be done by personnel with minimal training.
Although the study examined only the administration of flu vaccine with the dissolving microneedles, the technique should be useful for other immunizations. The future potential of this study aided its financing efforts, supported by the National Institutes of Health (NIH). If mass-produced, the microneedle patches are expected to cost about the same as conventional needle-and-syringe techniques, and may lower the overall cost of immunization programs by reducing personnel costs and waste disposal requirements, said Prausnitz.
Prausnitz believes that other opportunities might arise in the process. “The dissolving microneedle patch could open up many new doors for immunization programs by eliminating the need for trained personnel to carry out the vaccination,” he said. However, there is much to do before massive production can be executed. Clinical studies will have to be done to assure safety and effectiveness. Other vaccine formulation techniques may also be studied, and researchers will want to better understand why vaccine delivery with dissolving microneedles has been shown to provide better protection. “This approach could make a significant impact because it could enable self-administration as well as simplify vaccination programs in schools and assisted living facilities,” concludes Prausnitz.
TFOT has also covered the Type 1 Diabetes Nanoparticle Vaccine researched at the University of Calgary, Canada, and the development of nanoparticle vaccinations made by a student at the Ecole Polytechnique Fédérale de Lausunne, Switzerland. Another related TFOT story is that of the implantable cancer vaccine developed at Harvard University in Cambridge and the Dana Farber Cancer Institute in Boston.
For more information about the vaccine-delivery patch with dissolving microneedles, see Georgia Institute’s official press release.