Scientists have demonstrated the ability to deliver a dried live vaccine to the skin without a traditional needle, and shown for the first time that this technique is powerful enough to enable specialised immune cells in the skin to kick-start the immunising properties of the vaccine.
Researchers at King's College London say although it is an early study this important technical advance offers a potential solution to the challenges of delivering live vaccines in resource-limited countries globally, without the need for refrigeration.
A cheaper alternative to hypodermic needles, it would also remove safety risks from needle contamination and the pain-free administration could lead to more people taking up a vaccination.
The researchers added that it could have an impact beyond infectious disease vaccination programmes, for example managing autoimmune and inflammatory conditions such as diabetes.
The team at King's used a silicone mould developed by US company TheraJect to create a microneedle array - a tiny disc with several micro-needles made of sugar which dissolve when inserted into the skin. The team formulated a dried version of a live modified adenovirus-based candidate HIV vaccine in sugar (sucrose) and used the mould to create the microneedle array.
They found that the dried live vaccine remained stable and effective at room temperature.
To test the effectiveness of the microneedle array, they applied it to mice. Using imaging (in collaboration with Professor Frederic Geissmann, King's College London) they observed how the vaccine dissolved in the skin and were able to identify for the first time exactly which specialised immune cells in the skin 'pick up' this type of vaccine and activate the immune system.
The researchers found the first evidence that a sub-set of specialised dendritic cells in the skin were responsible for triggering this immune response.
When compared with a traditional needle vaccine method, the immune response generated by the dried microneedle vaccine (kept at room temperature) was equivalent to that induced by the same dose of injected liquid vaccine that had been preserved at -80 degree C.
The study, funded by the Bill and Melinda Gates Foundation, has been published n Proceedings of the National Academy of Sciences. (ANI)