Clinical Newswire

Skin Patch Delivers Simpler, Safer and More Efficient Influenza Vaccination

Zlatina Zlateva

28/Jul/10

Clinical Newswire, July 28, 2010 - Researchers have developed a way to deliver influenza vaccination through dissolving microneedle covered patches applied to the skin, according to a study published online on July 18 in Nature Medicine. The study, conducted in mice, found the new technology to result in improved immunogenicity compared to conventional intramuscular injection.

Traditional ways to deliver influenza vaccination by intramuscular injection generate biohazardous waste, can cause needle phobia and are also limited in effectiveness by the quality and scope of immune response they produce. New methods are therefore needed to achieve increased vaccine immunogenicity and high levels of mass immunization through better patient compliance.

The study by Mark Prausnitz and colleagues presents a simple and safe method for vaccine delivery by dissolving microneedle patches that painlessly pierce the skin. Since the skin is a highly active immune organ, it contains a large population of antigen presenting cells. Microneedles are micron-scale structures that administer vaccines in a targeted, minimally invasive manner. The microneedles for the present study were designed and fabricated using a biocompatible polymer encapsulating inactivated influenza virus to insert into skin without mechanical failure and rapidly dissolve into safe dissolution products. Using needles measuring only hundreds of microns in length not only eliminates pain, but also delivers the vaccine antigen to the abundant antigen-presenting cells of the epidermis and dermis of the skin.

The efficacy of skin immunization with dissolving microneedles was tested on mice that received a single dose of whole, encapsulated, inactivated influenza virus. The patches were applied for about 15 min which was sufficient to dissolve the microneedles and deliver at least 80% of the antigen into skin. Robust humoral and cellular immune responses were induced after a single immunization, leading to protective immunity against lethal viral challenge. Compared to intramuscular injection at the same dose, microneedle vaccination resulted in superior protective immune response, including 1000-fold more efficient lung virus clearance after challenge, described by the researchers as $B!H(Bkey immunologic difference$B!I(B between the two modes of vaccine delivery. According to the researchers, the improved lung virus clearance is expected to correlate with reduced morbidity and mortality.

$B!H(BThese results show that dissolving microneedle patches offer an attractive approach to administer influenza vaccine with improved safety, immunogenicity and logistical operations that may enable an increased population coverage for influenza vaccination$B!I(B, the study authors conclude. The microneedle vaccine patch developed in the study may also provide a new technology for simple administration of other vaccines and medicines through the skin, eliminating the need for hypodermic needles.