Study develops dissolvable microneedle patches for administering influenza vaccine

Study findings published online in The Lancet on June 27, 2017 have found that an experimental patch of dissolving microneedles can produce robust immune responses for influenza.

The microneedle patches can be administered safely and can be a substitute for the needle-and-syringe vaccination. With further advancements, they could remove the uneasiness in using an injection and inconvenience of visiting a flu clinic, as well as offering cost benefits.

"This bandage-strip sized patch of painless and dissolvable needles can transform how we get vaccinated," said Roderic I. Pettigrew, Ph.D., M.D., director of the National Institute of Biomedical Imaging and Bioengineering (NIBIB).

"A particularly attractive feature is that this vaccination patch could be delivered in the mail and self-administered. In addition, this technology holds promise for delivering other vaccines in the future."

The dime-sized vaccine patch contains 100 needles that are solid, water-soluble, and sufficiently long for skin penetration. “The skin is an immune surveillance organ." said Prausnitz who led the team that designed the microneedles patch for the study. "It's our interface with the outside world, so it's very well equipped to detect a pathogen and mount an immune response against it."

The vaccine is encapsulated in the microneedles. The needle tips dissolve to release the vaccine within minutes into the skin. The adhesive helps to hold the patch to the skin while administering the vaccine and the patch can be peeled and discarded just as a used strip of bandage.

The study enrolled 100 participants and these adults were randomly assigned to one among 4 groups:

• Group 1: Healthcare physician administered the vaccination with the microneedle patch
• Group 2: Study participants self-administered the vaccination with the microneedle patch
• Group 3: Healthcare physician provided the vaccination with an intramuscular injection
• Group 4: Healthcare physician gave a placebo microneedle patch

The research team vaccinated the participants in non-placebo groups using an inactivated influenza vaccine that was invented for the flu season in 2014–15.

While some of the study participants reported developing skin reactions to the vaccine patches such as faint redness and mild itching, which lasted for two to three days, the research found that the vaccination was safe with the microneedle patches with no reported adverse events.

Upon analyzing the blood samples, it was found that the antibody responses produced by the vaccine were similar in the groups that received patch vaccination and in the groups that received intramuscular injection.

Even after 6 months, these immune responses were still found to be present. Of the participants who received the patches, more than 70% preferred vaccination with patches to injection or intranasal vaccination in the future.

The study found that the participants could self-administer the patches correctly as there were no significant differences observed between the vaccine dosages when they were self-administered by the volunteers and when the vaccine was administered by the healthcare workers.

The imaging of the patches used showed that the microneedles dissolved in the skin after being vaccinated, signifying that the patches that are used can be safely disposed without the risk of sharp waste. The vaccines were found to be effective in the patches for a minimum of one year without being refrigerated.

It is expected that the prospective (vaccine) technology may offer economic and manufacturing benefits. The cost of manufacturing the patch is expected to be at par with the prefilled cost of syringes.

However, the patch can significantly reduce the vaccination cost as self-administering the patch could eliminate the requirement of a healthcare worker for overseeing the process. Packaging for transportation is easy; refrigeration is not required, and the patches are stable.

The research team is planning to carry out further clinical trials for pursuing the ultimate accessibility of the technology to patients and is also working toward developing microneedle patches to use with other vaccines such as measles, rubella, and polio.