Researchers at the University of Queensland and Vaxxas, a medtech company, announced the development of a high-density microarray patch (HD-MAP) that can deliver a COVID-19 vaccine through the skin without the need for needles. While such minimally invasive vaccine technology is to be welcomed, the major breakthrough is the temperature stability of the vaccine. The researchers were able to stabilize the formulation on the patch so that it can last for one month at room temperature and one week at 40 degrees Celsius (104 F), meaning that the new vaccine technology could help to overcome the cold chain transport hurdles.

Skin-affixed patches offer a variety of advantages over traditional needle injections, including less pain and irritation, and ease of use with people who have trouble with needles, such as young children. There has been a recent spate of microneedle technologies that are intended to deliver a variety of therapeutics through the skin, and it was perhaps only a matter of time before someone applied this technology to a COVID-19 vaccine.

However, the most exciting thing about this vaccine is perhaps not the HD-MAP delivery technology, but rather the logistical potential in its temperature stability. The researchers adapted their system to deliver the low-cost Hexapro vaccine, which was developed at the University of Texas.

“When the Hexapro vaccine is delivered via HD-MAP applicator – rather than a needle – it produces better and faster immune responses,” said David Muller, a researcher involved in the study, via a press release. “It also neutralizes multiple variants, including the UK and South Africa variants. And it’s much more user-friendly than a needle – you simply ‘click’ an applicator on the skin, and 5000 microscopic projections almost-imperceptibly deliver vaccine into the skin.”

The temperature stability of the vaccine could be a game changer in developing countries, where vaccine supplies have been slowed by the need for cold chain transport and cold storage.

“Hexapro, delivered by the high-density microarray patch, could dramatically assist global vaccine rollout effort, particularly for billions of vulnerable people in low- and middle-income countries,” said Muller. “We’ve shown this vaccine, when dry-coated on a patch, is stable for at least 30 days at 25 degrees Celsius and one week at 40 degrees, so it doesn’t have the cold chain requirements of some of the current options.”

So far, the researchers have tested the technology in mice, with promising results, and hope to progress to clinician trials soon.