Needlephobes, cower no more! Researchers at the Georgia Institute of Technology and Emory University have developed a vaccine-delivery patch that dissolves painlessly into your skin — no muss, no fuss, and no hypodermic needles or sharps to dispose of. You don’t even need medical personnel to inoculate someone. Slapping on the patch is virtually idiot-proof, allowing self-administration of vaccines during a pandemic or large-scale, walk-through immunization programs in developing nations.
A single patch contains hundreds of microscopic needles — each only 650 microns long — made from a polymerized blend of vinyl pyrrolidone and freeze-dried vaccine. Pressed against the epidermis, the microneedles quickly dissolve in bodily fluids, leaving behind only a thin backing that washes away in water.
Unlike traditional hypothermic needles, which deliver the vaccine into muscle, the patch penetrates the outer layers of the skin. Still, the latter may be a better point of entry, according to Richard Compans, professor of microbiology and immunology at Emory University School of Medicine. “The skin is a particularly attractive site for immunization because it contains an abundance of the types of cells that are important in generating immune responses to vaccines,” he says.
Although mice that were vaccinated by skin patch fought off an infection just as well as mice that were injected, researchers noted they also had far less viral activity in their lungs than their injected brethren. This suggests that the patch encourages a more effective immune response.
Another advantage that patch has over its forebears: the vaccine in the microneedles is present as a dry formulation, which improves its stability during storage and distribution.
For developing countries, the patch is a boon in more ways than one. Poor medical infrastructure frequently results in the reuse of hypodermic needles, a key contributor in the spread of diseases like HIV and hepatitis B. The dissolving microneedle patch would eliminate shared needles, while allowing vaccinations to be be performed by staff with minimal training.
The patch is expected to cost about the same as regular needle-and-syringe combos, but it could even lower the overall cost of immunization programs by reducing the need for expert personnel or waste disposal.