People with a fear of needles could one day be offered a patch alternative to a coronavirus jab.
At least one in 10 people has a phobia of needles, which may prompt millions to forgo life-saving vaccines.
To help combat this, scientists from the University of Queensland have developed a patch that could protect against the coronavirus with a single, pain-free "click".
The team put the device to the test on a group of mice, administering the experimental Hexapro vaccine, which is still in clinical trials.
The rodents were found to have "complete protection" against the coronavirus after a single dose.
The preliminary results have been published on the pre-print website bioRxiv and are yet to appear in a peer-reviewed journal.
The UK has four vaccines in its immunisation arsenal against the pandemic – Pfizer-BioNTech, University of Oxford-AstraZeneca, Moderna and Janssen – the latter of which is administered as a single dose, rather than a two-jab regimen.
While coronavirus deaths have plummeted in the UK, the pandemic is far from over "and we still face many challenges in the rollout of vaccines", wrote the scientists.
A team from the biotech firm Vaxxas – a spin-off of the University of Queensland – has therefore developed a "high-density microarray patch" (HD-MAP) to deliver the coronavirus' spike protein "directly to the skin".
The virus uses its spike protein to bind to a receptor on cells, allowing it to invade the body. Many vaccines are based on the spike protein, which the immune system then launches a response against.
Results suggest the HD-MAP "induced greater cellular and antibody [virus-fighting proteins] immune responses" in the mice than administering the vaccine as a shot.
The rodents' blood was able to "potently neutralise" the coronavirus, including the "variants of concern" that are thought to have emerged in Kent and South Africa.
The coronavirus vaccines were developed according to the variant that emerged in Wuhan, China – the former epicentre of the pandemic. New variants may evade the vaccines, however, experts are generally optimistic the jabs will still be at least somewhat effective.
"Finally, a single dose of HD-MAP" led to "complete protection" when the mice were exposed to the coronavirus, wrote the scientists.
"When the Hexapro vaccine is delivered via HD-MAP applicator, rather than a needle, it produces better and faster immune responses," said study author David Muller.
"It's much more user-friendly than a needle. You simply 'click' an applicator on the skin and 5,000 microscopic projections almost imperceptibly deliver [the] vaccine into the skin."
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The scientists believe the patch could be particularly useful in less developed parts of the world.
"We've shown this vaccine, when dry-coated on a patch, is stable for at least 30 days at 25°C [77°F] and one week at 40°C [104°F], so it doesn't have the cold chain requirements of some of the current options," said Muller.
In May, the European Medicines Agency announced that once the Pfizer-BioNTech vaccine has thawed, unopened vials could be stored in a standard fridge for up to one month – considerably longer than the previously advised five days.
The University of Queensland scientists are seeking "funding opportunities to accelerate to clinical trials as soon as possible".
David Hoey, CEO of Vaxxas, added: "These results are extremely clear, vaccination by HD-MAP produces much stronger and more protective immune responses against COVID-19 [the disease caused by the coronavirus] in model systems than via needle or syringe.
"The prospect of having a single-dose vaccine, that could be easily distributed and self-administered, would greatly improve global pandemic vaccination capabilities."
In the meantime, medics from Guy's and St Thomas' NHS Foundation Trust recommend people tell the person who is administering the vaccine about any fears they have.
The administrator may be able to calm your concerns or distract you while delivering the jab.
Relaxing breathing exercises may also help you get through the vaccination process.
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