Injection-free vaccination technique shows promise

By Helen Albert, Senior medwireNews Reporter

Study findings show that a new injection-free vaccination technique, applied through a patch on the skin, can induce the same level of immune response as a standard vaccine injection when given to mice.

The researchers used a dried version of a candidate live HIV vaccine, a vaccine type that would normally require transportation and storage in a cold environment (typically a maximum of 8°C, although generally cooler). However, the dried vaccine appeared to remain stable and effective when kept at room temperature.

"This work opens up the exciting possibility of being able to deliver live vaccines in a global context, without the need for refrigeration," said study author Linda Klavinskis (Kings College London, UK) in a press statement.

"It could potentially reduce the cost of manufacturing and transportation, improve safety (as there would be no loss in potency), and avoids the need of hypodermic needle injection, reducing the risk of transmitting blood-borne disease from contaminated needles and syringes," she added.

As reported in the Proceedings of the National Academy of Sciences, Klavinskis and colleagues used a silicon mold to create a microneedle array made of a dried version of the adenovirus-based candidate HIV vaccine combined with sucrose.

When tested in laboratory mice, the team found that the vaccine dissolved effectively in the skin and triggered an immune response of a very similar nature to that stimulated by conventional vaccine delivery. More specifically, CD8+ T-cell expansion was observed, in addition to multifunctional cytokine responses.

The degree and type of immune reaction triggered by the microneedle array vaccination technique was equivalent to that produced by the same dose of the vaccine injected in the standard fashion and stored at -80°C.

The researchers showed that the vaccine was distributed in both the dermis and epidermis, with CD11c+ dendritic cells playing a key role in acquiring and distributing the vaccine further around the body.

"This new technique represents a huge leap forward in overcoming the challenges of delivering a vaccination programme for diseases such as HIV and malaria," commented Klavinskis.

"But these findings may also have wider implications for other infectious disease vaccination programmes, for example infant vaccinations, or even other inflammatory and autoimmune conditions such as diabetes," she concluded.

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