A small, dissolvable patch boasting an array of tiny needles could offer a safe relatively painless alternative to traditional injections for vaccination against flu, researchers have found.

The approach is likely to be welcomed by those who shudder at the sight of a needle, but it could also provide other benefits.



Not only do the patches offer a low-cost procedure and reduce dangerous waste, but they can be applied by the patient and do not need to be kept cold since they are stable at 40C for a year. Researchers say that is a valuable bonus when it comes to providing vaccines to populations in developing countries.

“I think this product would greatly simplify access to vaccines and perhaps improve coverage as well,” said Nadine Rouphael, a co-author of the research and associate professor of medicine at Emory University School of Medicine.

In the UK complications from seasonal influenza alone kill about 600 people a year while in the US it has been found to account for tens of thousands of deaths a year.

While dissolvable microneedle arrays are already used in the cosmetic industry, including for the delivery of botox, the new study looked at their potential in flu vaccination.

The team compared traditional needle-and-syringe methods with the use of sticky patches made from sucrose and polyvinyl alcohol, each containing an array of 100 micro-needles – tiny protrusions less than a millimetre in height.



For the study, 100 adults aged between 18 and 49 who had previously chosen not to have the flu vaccine were recruited and randomly sorted into four groups, one of which received a traditional injection into the muscle of the arm.



In the first human trial of its kind, those in the other three groups all applied a patch to the wrist for 20 minutes, allowing the microneedles time to dissolve before the backing was removed and disposed of. One group received a placebo and the other two groups received the flu vaccine, the patch administered by a healthcare worker in one case and by the patient themselves in the other. A snap system was incorporated into the device to let users know when enough pressure had been applied to the patch.

All participants were then assessed for 180 days, and adverse events and antibody levels measured.

Published in the Lancet by Rouphael and colleagues at Emory University and Georgia Institute of Technology, the results reveal that none of the participants in any of the groups showed any serious adverse events and the mild side effects seen were similar for all of those vaccinated, regardless of method.

Both approaches were found to cause tenderness in some patients, but 96% of those vaccinated with the patch said they found the technique pain-free.

Antibody response to three different strains was just as good with the patch, and 70% of those vaccinated by microneedles said they preferred the method to traditional injections or intranasal methods.

“It is easy to administer, people are comfortable doing it for themselves, it dissolves very nicely,” said Rouphael.

The team caution that the study’s participants were potentially less keen than the average person to have a traditional flu shot.



Further, larger-scale trials are now needed, said Rouphael, adding that it will still be a few years before the patches will be available for flu vaccination.

She mooted a situation where, in the case of a flu pandemic, microneedle patches could be distributed en masse, offering individuals a method of vaccination that did not require to visit a doctor or clinic, which would risk exposure to the virus.



Linda Klavinskis, an immunobiologist at King’s College London, said the research was a step forward but challenges still remain, including how to elicit a stronger immune response from elderly patients and how to increase the potency of the vaccine used – an important consideration in the case of a pandemic, when supplies are stretched.

John McCauley, director of the Worldwide Influenza Centre at the Francis Crick Institute in London, said the research could lead to higher uptake rates of vaccines. “I think it is really quite a promising way forward,” he said, adding that further studies are needed to show that the approach offers benefits in the event of an influenza epidemic.

“If you can make [vaccination] easier, more people will take it. With more people taking it there is better ability to control infection at the population level,” he added.