Editors' ChoiceVaccines

Protecting kids with a patch

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Science Translational Medicine  19 Oct 2016:
Vol. 8, Issue 361, pp. 361ec169
DOI: 10.1126/scitranslmed.aai9165

Respiratory syncytial virus (RSV) is the most common cause of hospitalization in young children, with 60% of children infected within their first year of life. Although RSV infections affect infants most severely, RSV continues to infect humans with age and can result in pneumonia and lung inflammation. A vaccine for RSV has remained elusive, in part due to the failure of infection to induce immunity that prevents reinfection, as well as the risk of immune-mediated disease exacerbation.

In a new study, Hervé and colleagues used an epicutaneous skin patch to deliver an RSV antigen to protect against RSV infection in mice and pigs. The skin patch, termed Viaskin, is an adhesive, needle-free device containing spray-dried RSV antigen. Upon application, the patch forms a condensation chamber with the skin and uses perspiration to solubilize the antigen, facilitating its transport into the epidermis. The antigen used in this study was an RSV nucleoprotein nanoring consisting of RSV nucleoprotein bound to a bacterial RNA backbone assembled into 15 nm nanorings.

The skin patch vaccine was tested in both mouse and pig animal models, the latter of which represents the best available model of human skin. After patch application to pig skin, the abundant dendritic cells called Langerhans cells within the epidermis efficiently took up the antigen. Six patches were applied over the course of 3 weeks, with each patch administered for a 48-hour period. Both mice and pigs mounted anti-RSV immune responses that included strong CD8 and CD4 T cell responses. Furthermore, a local immune response mediated by T helper 1 (TH1) and TH17 cells was noted in mice.

This patch-based approach may promote enhanced immunity compared with traditional vaccine administration by intramuscular injection, since more immune cells reside in epidermis than in muscle. As a painless mode of delivery, patches will facilitate RSV vaccination in children, with potential extension to alternative vaccines. Future work is needed to thoroughly evaluate the potential for unwanted lung inflammation and other vaccine-related immune responses that may adversely affect disease outcomes. Clinical translation may also require a reduction in the number of patch applications necessary to achieve therapeutic effect.

P.-L. Hervé et al., Non-invasive epicutaneous vaccine against Respiratory Syncytial Virus: Preclinical proof of concept. J. Control. Release 10.1016/j.jconrel.2016.10.003 (2016). [Full Text]

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