Skin patch coated in covid-19 vaccine may work better than injections
A skin patch for administering covid-19 vaccines gives greater immune protection than traditional injections, according to a study in mice. The patch can be stored at room temperature and be self-administered, making it suitable for use in places that lack cold storage facilities and medical staff.
Although covid-19 vaccines are now widely available in many countries, they have to be transported and stored at cold temperatures. “We wanted to come up with an alternative that would be stable long enough to go that last mile, especially in resource-limited settings,” says David Muller at the University of Queensland in Brisbane, Australia.
Muller and his colleagues have spent years developing a skin patch that can deliver influenza, polio, dengue and other vaccines without requiring needles or cold storage. They wondered if the same technology could be used for covid-19 vaccines.
The centimetre-wide skin patch is dotted with 5000 tiny plastic spikes, each a quarter of a millimetre long and coated with dried vaccine that is more stable than liquid forms. The patch is applied with an applicator that painlessly presses the vaccine into the upper layer of the skin.
Vaccines delivered this way tend to elicit stronger immune responses because the skin is full of immune cells, says Muller. For example, when the flu vaccine is administered via this skin patch, a sixth of the normal dose can be used because it produces a stronger response.
The researchers tested the skin patch with a covid-19 vaccine candidate called HexaPro, developed by researchers at the University of Texas at Austin, which is still being tested in clinical trials but is more heat stable and cheaper to make than existing vaccines.
The HexaPro vaccine was stable for at least one month in the skin patch when stored at 25°C and for one week at 40°C.
A trial of the covid-19 vaccine skin patch in people will begin next year. If it is approved, it could be used to deliver booster doses and potentially to protect against new virus strains, since it is easy to adapt HexaPro to different variants, says Muller.
News Credit: www.newscientist.com