This could be goodbye to arm jabs – no need to rollup to receive your medicine

Most current vaccinations use needles and syringes. However, needles can spread infections if they are reused and many people live in fear of the pain they can cause.

Single use needles are fine, but too expensive for regular use in poorer countries. Therefore, scientists are seeking alternatives such as liquid-jet injectors, skin application, pills and nasal sprays.

University of Queensland scientists have successfully immunised mice from the Covid virus by administering a US-developed vaccine on a skin patch applied with a single, pain-free ‘click’ from a pocket-sized applicator.

The patch – a HD-MAP applicator – developed by the University of Queensland (UQ) and Vaxxas Pty Ltd has thousands of vaccine-coated micro-projections. When it is applied to the skin for a few seconds it delivers vaccines to the immune cells immediately below the skin surface.

The vaccine used in the trial was the University of Texas Hexapro vaccine. It is stable for at least 30 days at 25°C and one week at 40°C when dry coated on a patch.

“It doesn’t have the cold chain requirements of some of the current options,” said Dr David Muller from UQ’s School of Chemistry and Molecular Biosciences.

“The vaccine patch produced strong immune responses that were shown to be effective when mice were exposed to SARS-CoV-2 – the virus that causes Covid-19. 

“When the Hexapro vaccine is delivered via HD-MAP applicator – rather than a needle – it produces better and faster immune responses,” he said. 

“It also neutralises multiple variants (of the virus), including the Delta and Omicron 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.” 

“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,” he said. 

Needle-free immunisations was first used for the oral polio vaccine. This vaccine, which contains live attenuated poliovirus, generates immunity by infecting the gastrointestinal tract. Attenuated vaccines are weakened virus mutants that stimulate immune responses but not infectious.

Other oral vaccines include typhoid fever, cholera, rotavirus and nasal influenza. However, oral vaccination only works with vaccines containing living organisms which can survive stomach acids and enzymes and infect the intestinal tract.

Several other vaccines, such as the Sabin oral polio vaccine, have been given via the mouth or, in the case of some ‘flu vaccines by nose spray. However, vaccines administered by this route are sometimes deactivated by enzymes in the mouth or nose, 

Another needle-free method is a liquid-jet injector that produces a very narrow high-velocity vaccine jet. The liquid jets penetrate the skin and deliver the vaccine into the skin, subcutaneous tissue or the underlying muscle. Unfortunately, liquid-jet injectors cause more-frequent site reactions such as soreness, redness and swelling of the injection site, compared to needles.

Writing in Nature Reviews Immunology bioengineering professor Samir Mitragotri of Harvard University, said no one method of needle-free immunisation is superior in all circumstances. So jabs will continue to be needed for some diseases.

The University of Queensland research was published in Science Advances late last year. 

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Frank Smith was trained as an agricultural scientist in the UK, moving to WA in 1974 and shortly afterwards began lecturing at WAIT (now Curtin University) in soils and agronomy. In 1979 he joined the Agriculture Protection Board in charge of publications and media relations, studying part time for a degree in Journalism. In 1992 he spent a year as a visiting professor at the University of Missouri-Columbia. Later he ran a small publication company with his wife Mary-Helen. He then began freelance writing, editing and book indexing. He has written articles for more than 40 magazines in four continents and indexed more than 20 books. In 2007 he started writing for Have a Go News and gradually reduced his writing for other publications. He later took over the subediting, ensuring Have a Go News is consistent in style and highly readable. He and Mary-Helen live in a passive solar home in the Perth Hills with a varying collection of quendas and native birds.