Needle-free vaccinations are a step closer with the announcement of a successful trial in rodents. Besides taking the pain out of childhood trips to the doctor, the nanopatch technology used in this experiment could make vaccines cheaper and more widely available, potentially saving millions of lives.
Although vaccination has freed the world of smallpox and prevented vast amounts of suffering and death from other diseases, challenges remain, even for the viruses and bacteria where vaccines exist.
Most vaccines require both refrigeration and health professionals to deliver them, which can hamper delivery in regions without electricity or advanced medical systems. Some are in short supply, and the act of injecting may be part of the reason anti-vaccination fears persist, in the face of overwhelming evidence.
The nanopatch, developed by Professor Mark Kendall of the University of Queensland, is regarded as one of the more promising alternatives to hypodermic needles. It relies on thousands of tiny silicon projections, each delivering a minuscule dose of vaccine into the skin. Now a trial of the nanopatch has demonstrated its effectiveness in delivering the inactivated type 2 poliovirus vaccine to rats.
The team responsible for the new method of vaccination. University of Queensland
Dr. David Muller, first author of the paper in Scientific Reports that announced the trial, told IFLScience the patch is “applied like a stamp” and stays on for two minutes. One advantage of the Nanopatch is that it requires less vaccine to be effective, allowing for "dose-sparing" where the same quantity is spread over more recipients.
“We compared the Nanopatch to the traditional needle and syringe, and found that there is about a 40-fold improvement in delivered dose-sparing ,” Kendall said in a statement. “To our knowledge, this is the highest level of dose-sparing observed for an inactivated polio vaccine in rats achieved by any type of delivery technology, so this is a key breakthrough.”
The team attribute the nanopatch's efficiency to its delivery to areas rich in immune cells. “The Nanopatch targets the abundant immune cell populations in the skin’s outer layers; rather than muscle, resulting in a more efficient vaccine delivery system,” Muller said in a statement.
Two vaccines exist against polio, and together they have eliminated the once-widespread scourge from most of the planet. As long as polio maintains its presence in Pakistan and Afghanistan, though, there is potential for outbreaks to spread more widely, as occurred last year in Ukraine.
However, Muller told IFLScience that the oral attenuated vaccine is being phased out in favor of the inactivated version in response to concerns that people inoculated with the attenuated version can shed the vaccine-derived virus, potentially infecting others.
The nanopatch has the potential to offer the best of both worlds – requiring no refrigeration and able to be distributed by relatively untrained volunteers like the oral version but, similar to inactivated injections, free from the risk of vaccine-derived outbreaks. Moreover, the nanopatch's efficiency could be useful given a global shortage of the inactivated vaccine, which Muller says has forced some countries to continue use of the oral version.
The nanopatch is being commercialized by Vaxxas Pty Ltd. Vaxxas CEO David Hoey said the first human vaccination studies are scheduled to start this year. Kendall's team are also working on applying the nanopatch to other diseases.
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