Study suggests that self-administration of influenza vaccine may be feasible with microneedle patch

There are many reasons some people may not get a flu shot, but would they be more likely to do so if there was a simple device that could be mailed directly to them, was easy enough to use by themselves, and provided at least the same level of protection as a traditional flu shot without the pain of a needle jab? A recent NIBIB-funded study, published online February 2014 in the journal Vaccine, suggests the answer is yes.

Nearly 100 healthy adults took part in a study led by Mark Prausnitz, Ph.D., of the Georgia Institute of Technology, on their ability and willingness to use a microneedle patch. The patch consists of 50 tiny needles, each about as tall as a credit card is thick, arranged at the center of a thin, flexible foam pad about the size of an adult fingertip. Each participant was provided three microneedle patches to apply to his or her own forearm; none of the patches used in this study had influenza vaccine. The participants also had one microneedle patch applied by a trained researcher and were administered one intramuscular injection of saline with an inch-long needle, similar to syringes used for traditional flu shots, also by a trained researcher. Participants noted a fairly low level of pain from the intramuscular injection—15 on a scale of 1-100, with 100 being the highest level of pain—while the microneedle patch was generally rated far lower at 1.5 out of 100, whether self-administered or administered by a study investigator.

Most participants were able to apply the patches correctly by themselves on the first try. Some participants were given an applicator that made an audible click when the patch was applied with proper force—about as much pressure as needed to fasten a typical clothing snap. Such a device could help assure patients that they used the patch correctly.

Besides being easy to use, the microneedle patch is also much smaller than typical flu vaccine supplies and does not need to be refrigerated, meaning it could potentially be sent through the mail or made available outside of traditional healthcare settings. Before trying out the microneedle patches, only 44 percent of study participants said they planned to get a flu shot that year, slightly higher than average immunization coverage for U.S. adults between 2010-2013.² Within this group, most participants would prefer to use the microneedle patch themselves either at home or with a healthcare worker nearby. Reducing the number of patients waiting in clinics or doctors' offices to get a flu shot could translate to lower healthcare costs for flu vaccination programs.

Even more importantly, the patch could significantly increase the rate of immunization, providing better protection for the public as a whole. Among study participants who did not plan to get a flu shot that year, 38 percent said they would vaccinate if self-administration of the microneedle patch was an option. Such a dramatic increase, if reflected in the general population, could greatly limit lost productivity due to flu-related work absences and reduce flu-related hospitalizations and deaths.

Prausnitz and colleagues plan to start a clinical trial in the spring of 2015, with the goal of making the microneedle vaccine patches available within five years.