A hi-tech skin patch that can deliver vaccines painlessly could lead to the end of traditional flu jabs, US researchers have found.
The patches, which contain scores of tiny needles, can be used by someone who has no medical training.
It has been successfully tested on mice and, according to scientists, it can "vaccinate against influenza at least as well, and probably better than, a traditional hypodermic needle".
The patch's "microneedles" - measuring about half a millimetre - deliver the vaccine before dissolving. The only thing left is a water-soluble backing that can be thrown away.
Scientists first created a 100-needle patch that was tested on pig skin, which is about the same thickness as human skin, before carrying out flu vaccine tests on mice.
One group of rodents received hypodermic needle flu jabs while others were treated with patches 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 jab.
Professor Mark Prausnitz, from the Georgia Institute of Technology in Atlanta, who led the study reported 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."