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Painless patches may replace flu jabs
19 Jul 2010Traditional flu jabs could be rendered obsolete by a hi-tech skin patch which delivers vaccine painlessly through scores of tiny needles.
Scientists believe the patch, successfully tested on mice, could revolutionise pandemic control by allowing vaccines to be self-administered.
The patch can easily be used by someone with no medical training.
After it is applied to the skin, the "microneedles" - each measuring just over half a millimetre - deliver the vaccine and simply dissolve away. All that remains is a water-soluble backing that can safely be discarded,
Scientists in the US designed a 100-needle patch that was first tested for its ability to penetrate pig skin, which is about the same thickness as its human counterpart.
They then carried out experiments to see how effectively the patch could deliver flu vaccine in mice.
One group of rodents received hypodermic needle flu jabs, while others were treated with patches that were either loaded with the vaccine or empty.
Three months later mice vaccinated with the microneedles were found to be mounting a stronger immune response than those injected by syringe.
They were better able to clear the flu virus from their lungs than animals given the traditional flu jab.
Professor Mark Prausnitz, from the Georgia Institute of Technology in Atlanta, who led the study reported today in the journal Nature Medicine, said: "We have shown that a dissolving microneedle patch can vaccinate against influenza at least as well, and probably better than, a traditional hypodermic needle."
The needle arrays are made from a plastic-like polymer that is known to be safe for use in the body.
Freeze-dried vaccine was mixed into the material in tiny moulds.
The patch could aid mass-immunisation in poor parts of the world, where re-use of hypodermic needles leads to the spread of infections such as HIV and hepatitis B.
"We envision people getting the patch in the mail or at a pharmacy and then self-administering it at home," said Dr Sean Sullivan, another member of the Georgia team. "Because the microneedles on the patch dissolve away into the skin, there would be no dangerous sharp needles left over."
Although the study focused on flu, the technique could also be useful for other vaccines, say the scientists.
Mass-produced microneedle patches are expected to cost about the same as conventional jabs. However, the overall cost of immunisation programmes using patches may be lower because of the reduced need for personnel and waste disposal.
Before being made generally available, the patch will have to undergo patient trials to assure its safety and effectiveness.
Prof Prausnitz said: "The dissolving microneedle patch could open up many new doors for immunisation programmes by eliminating the need for trained personnel to carry out the vaccination.
"This approach could make a significant impact because it could enable self-administration as well as simplify vaccination programmes in schools and assisted living facilities."
