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COVID-19 Vaccine Patch Is Better And Faster Than Injection In Mouse Trials


Dr. Katie Spalding

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory.

Freelance Writer


The high-density microarray patch, developed by Vaxxas, offers an effective needle-free vaccine delivery system. Image: Vaxxas

The COVID-19 vaccines currently available are pretty darn good, all things considered – but there are always ways to improve. Personally, we’d like somebody to invent a vaccine that tastes like chocolate, but that may be a while away for now.

Other people, though, have more legitimate concerns (and no, we’re not talking about those “legitimate concerns.”) Trypanophobia, or a severe phobia of needles, can be a debilitating condition – one that leads one in six Americans to straight-up skip their annual flu shot. But a new COVID-19 vaccine being tested by the University of Queensland, Australia might have the answer: it comes as a patch, not a needle.


“[I]t’s much more user-friendly than a needle,” explained Dr David Muller of the University of Queensland School of Chemistry and Molecular Biosciences. “You simply ‘click’ an applicator on the skin, and 5000 microscopic projections almost-imperceptibly deliver vaccine into the skin.”

In a paper published today in the journal Science Advances, Muller and team described how the patch vaccine successfully protected mice against exposure to SARS-CoV-2 – the virus that causes COVID-19. Even better, the immune response triggered by the patch was stronger than the same vaccine delivered by needle.

“When the … vaccine is delivered via HD-MAP applicator [patch] – rather than a needle – it produces better and faster immune responses,” Muller said. “It also neutralises multiple variants, including the UK and South Africa variants.”

The vaccine is delivered via 5,000 almost impercetible microscopic projections. Image credit: Muller et al, 2021

Needle-phobics aside, this could be a massive breakthrough for people in poor and developing countries, the researchers said. The vaccine used in the trial was the University of Texas candidate HexaPro, developed in the hopes of advancing low-cost and widely distributable vaccines. It can be stored at temperatures as high as 8°C (46.4°F), removing the need for specialist freezers, and it is made in eggs, just like flu vaccines – meaning the infrastructure to produce them is already established around the world.


“We are witnessing unprecedented disparities in COVID-19 vaccine access around the world,” said Ilya Finkelstein, one of the team who developed HexaPro, in a statement back in April. “We designed HexaPro to … bring us a step closer towards addressing the wide disparity in vaccine access.”

The patch delivery system develops that mission further: the vaccine proteins are stable on the patch for up to a month at 25°C, and a week even at temperatures as high as 40°C, the paper reveals.

“Should this measure of stability translate to biophysical stability, this represents a marked improvement over other SARS-CoV-2 vaccine candidates,” the paper explains. “This lends itself well to improvements in vaccine transport and delivery to patients, especially in a “last-mile” context where appropriate infrastructure may be limited. This is particularly relevant to low-to-middle income countries … where there is an urgent need to facilitate vaccination of populations against SARS-CoV-2.”

The patch is just about the size of a fingertip. Image: Vaxxas

Currently, almost exactly half the world’s population has received at least one dose of a COVID-19 vaccine – but that number is heavily skewed in favor of high-income countries like the US. While three-quarters of Canadians and Europeans are already double-vaccinated – and one in 10 Brits have even received a third shot – about 96 percent of people in low-income countries have yet to receive a vaccine.


Now that the vaccine has proved effective in mice, the team are hoping to start clinical trials “as soon as possible,” Muller said. Together with Vaxxas, the company that commercialized the patch delivery system, the researchers hope they will soon be able to increase vaccine delivery across the world.

“These results are extremely clear – vaccination by HD-MAP produces much stronger and more protective immune responses against COVID-19 in model systems than via needle or syringe,” said David Hoey, President and CEO of Vaxxas. “The prospect of having a single-dose vaccine, that could be easily distributed and self-administered, would greatly improve global pandemic vaccination capabilities.”


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