Hate injections? Engineers are trying to end them forever

A new wave of technologies are finding new ways to deliver life-saving drugs and vaccines

Getting a needle poked into your arm isn’t anyone’s idea of fun. But for some, it’s not just an unpleasant experience: needle-phobia is a legitimate condition that can prevent them from getting the medicines they need. 

It’s estimated that up to 20% of the population suffer from a fear of needles. The condition has public health ramifications too: it's a major reason why people don't return for follow-up vaccinations. 

In fact, it’s considered such an enduring problem that in January 2024, UK Research and Innovation announced it would be investing up to £1 million in projects that investigate needle-free technology to dole out medicines. There are other benefits to forgoing needles too: it’s better for the environment and reduces medical waste. Needle-free modes of delivery could also greatly extend the shelf life of certain drugs, which wouldn’t need to be kept at a specific temperature. 

While vaccine hesitancy is a complicated problem, given that one facet behind it is an aversion to needles, researchers have been trying to come up with less prickly ways of delivering vaccines for decades. “If you can take out the needle, that's something that you can technologically address” to increase uptake, says Darcy Dunn-Lawless. 

Dunn-Lawless, a doctoral student at Oxford University, has thrown his own approach into the ring. He’s developing a platform in which vaccines can be delivered via ultrasound, rather than the poke of a needle. Not only could it offer a workaround for needle delivery, but it’s possible it could stimulate an even better immune response with a lower amount of drugs, he says. 

It works through a process called cavitation: where bubbles move in response to ultrasound, and the bubbles can be used as a pump to move the vaccine molecules deep into the skin. So far, they’ve just tested the approach on animals, in a study in mice. Dunn-Lawless says they didn’t see any side effects, except for some temporary reddening of the skin. In another study, they found that even though there were about 700 times fewer vaccine molecules that actually made it into the skin using the ultrasound approach versus needle, the mice still actually had a significantly higher immune response. The reason why, Dunn-Lawless says, is potentially because the ultrasound blasts the molecule into the skin; it may also be making the cells more permeable to the molecules as well. The next step Dunn-Lawless is focusing on is building the first prototype of the device. They also want to run challenge trials in mice, in which they expose the animals to the disease against which they’re vaccinating. 

Dunn-Lawless is not the only one trying to come up with needle-free approaches; in fact, researchers have been trying for decades, with varying degrees of success. In the middle of the 20th century, a new innovation called jet injectors promised to do away with needles, forcing vaccines through the skin using pressure. In reality, the devices turned out to be even more painful than the needles themselves, and posed a biohazard due to the tips of the injectors becoming coated with patient fluids and spreading hepatitis. Other needle-free ways of administering vaccines have emerged since: vaccines delivered via the mouth or nose gained traction during the Covid-19 pandemic, and more could be coming soon. 

And the idea of the jet injector also hasn’t completely disappeared. During the pandemic, it occurred to Jeremiah Gassensmith, an associate professor of chemistry and biochemistry at the University of Texas at Dallas, that the looming huge vaccination drive was going to rely on needles – and all their drawbacks. He and his team had been working on the idea of encapsulating antigens or vaccines inside of a nano-coating, which stabilises the vaccines so you can actually just dry it out as a powder. 

Using materials he ordered online, Gassensmith designed a vaccine delivery method that involves first taking the vaccine in a powdered form, and injecting it into the skin using compressed gas using a jet injector he designed, called the MOF-JET. (He tried out shooting himself with it: “it feels like getting hit with a Nerf dart,” he says.) The powder form doesn’t have that “splash-back problem” the older models had, according to Gassensmith. So far, they’ve trialled the application in animals, with promising results – it was as effective as a needle. At the moment, they’re refining the engineering of the device to make it more efficient but after that, they want to move to human trials. 

While these newfangled methods are still moving through the slow process of being proven to be safe and effective in humans, the research seems promising. One day, getting pricked by a needle may be a thing of the past. 

This project was funded by:

Through the Health Innovation call.