Getting an injection is on the bottom of everybody's list of favorite things, but now a more bearable alternative is another step closer to reality. In human clinical trials, painless microneedle patches have been found to be just as effective at delivering flu vaccines, and are easier to administer, transport, store and dispose of than regular needles.

As their name suggests, microneedle patches are stick-on patches containing an array of tiny plastic needles. Placed on the skin like a Band-Aid, these needles dissolve over a short time, delivering the vaccine payload into the bloodstream. Not only is the technique reportedly painless, but because the vaccine is dried it doesn't need to be refrigerated during transport or storage, and the dissolving needles mean the used patch can be safely thrown out without the hazard of sharps waste.

Since it can be applied like a nicotine patch, the vaccine is also easy enough for people to use at home. Busy people – or those actively avoiding the unpleasantness of the experience – might not bother going to the doctor's office for a flu shot, but the researchers hope that the convenience of the patch will encourage more people to get vaccinated every year, a number which currently hovers around 40 percent of US adults.

"Despite the recommendation of universal flu vaccination, influenza continues to be a major cause of illness leading to significant morbidity and mortality," says Nadine Rouphael, first author of the study and principal investigator of the clinical trial. "Having the option of a flu vaccine that can be easily and painlessly self-administered could increase coverage and protection by this important vaccine."

The clinical trials began in June 2015 with 100 participants aged between 18 and 49, who hadn't received a flu shot in the past year. They were divided randomly into four groups: one received microneedle patch vaccines from a doctor, others applied it themselves, some were given a standard flu shot by way of injection, and a fourth group were given a placebo patch.

The study reported that the antibody responses were very similar across all three non-placebo groups. The microneedle patch performed about the same as an injection, regardless of whether the patient had administered it themselves or had a doctor do it. Over 70 percent of the participants who received the patch said they would prefer it over an injection in future.

There were no adverse effects either, apart from some faint redness of the skin around the patch site, and some mild itching for a couple of days. The team also found that the drugs in the patch could stay viable for over a year, without the need for refrigeration.

"With the microneedle patch, you could pick it up at the store and take it home, put it on your skin for a few minutes, peel it off and dispose of it safely, because the microneedles have dissolved away," says Mark Prausnitz, senior co-author of the study. "The patches can also be stored outside the refrigerator, so you could even mail them to people."

Encouraged by the success of this first trial, the team hopes the next phase will be underway soon. In future, vaccines against other diseases like measles, rubella and polio could be administered via microneedle patch.

"It's very gratifying and exciting to have these patches tested in a clinical trial, and with a result that turned out so well," says Prausnitz. "We now need to follow this study with a phase II clinical trial involving more people, and we hope that will happen soon."

The study was published in the journal The Lancet. The team describes the technology and trials in the video below.

Source: Georgia Tech

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