A new needle-free vaccine approach: Ultrasound delivery

Did you get your annual respiratory virus vaccines this year? 

Once again, COVID and flu vaccination rates are not where global public health officials wish for them to be. Medical misinformation and vaccine hesitancy are worthy opponents for even the most health-minded in our society.

But even for those of us who do diligently get our annual shots, we can’t deny that it can be an unpleasant experience. At the very least, the injection-site arm soreness can be a literal pain.

What if we told you the vaccines of the future won’t have this problem?

University of Oxford researchers have created a needle-free vaccine delivery system using ultrasound.

Is this our new solution to vaccine hesitancy? And will your shoulders get a break during your next physical? Let’s find out.

No more needles at your annual checkup?

Not so fast.

So far, researchers have only tested the model in animals, so we won’t be benefiting from this technology right away.

But the way it works is fascinating.

The researchers first mixed vaccine molecules with tiny cup-shaped protein molecules in a liquid. They then applied the liquid to the skin of mice and exposed it to ultrasound for a minute and a half.

What happens next is called cavitation. In response to the sound waves, bubbles form and pop on the surface of the skin. The concentrated mechanical energy produced by these small but mighty bubbles allows the vaccine molecules to enter the upper layers of skin.

Of course, injecting a vaccine straight into a muscle is still a more direct path to delivering a greater amount of vaccine molecules into the body. The researchers’ mice study reported 700 times fewer vaccine molecules delivered via the cavitation approach than traditional injection.

However, the cavitation approach produced a higher immune response. Why might that be?

The researchers theorize that the concentration of immune system cells in the skin along with the ultrasonic delivery targets may be behind this higher response.

What about side effects?

“In my opinion, the main potential side effect is universal to all physical techniques in medicine: If you apply too much energy to the body, you can damage tissue,” Oxford biomedical engineer Darcy Dunn-Lawless said. “Exposure to excessive cavitation can cause mechanical damage to cells and structures. However, there is good evidence that such damage can be avoided by limiting exposure, so a key part of my research is to try and fully identify where this safety threshold lies for vaccine delivery.”

The result? A potentially more efficient and low-risk vaccine that can help reduce vaccination costs—and potentially help lower vaccine hesitancy.

Tackling the global crisis of vaccine hesitancy

Of course, we’re a long way off from seeing ultrasound vaccination in the doctor’s office. But if your heart leapt with relief at the thought of a needle-free alternative to vaccination, you’re not alone. 

Needle anxiety—also known as trypanophobia—is real. In fact, researchers have found it’s one of the significant reasons behind vaccine hesitancy. One study found that 1 in 4 adults surveyed had a fear of needles.