Two exciting new alternatives to needle and syringe vaccines could have a considerable impact on global health. One such method is the Nanopatch™, a fingertip-sized patch covered in thousands of vaccine-coated microscopic spikes, developed by Professor Mark Kendall and his research team at the University of Queensland’s Institute for Biotechnology and Nanotechnology. The team tested their Nanopatch on mice using inoculations for flu, the human papillomavirus (HPV) that causes cervical cancer, and a potential new vaccine against the mosquito-borne viral disease chikungunya. According to Kendall, the team demonstrated that only a tiny fraction of the dose required for needle vaccination is needed to achieve the same immune response with the Nanopatch.
Needle and syringe vaccines are typically administered into the muscle which has relatively few immune cells. Over the last 30 years or so, immunologists have discovered that skin is crammed full of immune cells, making it a far more effective place to apply vaccines. “You could argue that the skin is our immune sweet spot,” said Kendall.
When people allow their fear of needles to prevent them from becoming immunized, it can lead to disease and death. Kendall affirms that 20% of the population have needle phobia. Another consideration is the fact that 1.3 million deaths a year can be attributed to contamination injuries.
Needle and syringe vaccines need to be chilled throughout their life-cycle to prevent temperature damage that can render them ineffective or potentially harmful. This cold chain process is costly and makes it difficult to distribute vaccines to many parts of the world. The coating formulations used to coat the Nanopatches provides the vaccine with ambient temperature stability that eliminates the need for the cold chain, saving money and simplifying global distribution.
Kendall’s Nanopatch has yet to prove itself in human clinical trials, but has shown impressive results in animal tests. He hopes to move forward with full clinical trials on humans starting this year in Australia and Papua New Guinea with a $100,000 enterprise award from Rolex to help along the way. The device could have a significant impact on global health.
“This could potentially change the world of vaccinations. But we still have a very long way to go,” says Kendall. He explains more about the device in a TED talk.
Another significant development in needle free immunization is a dry-spray technology developed by Harvard School of Public Health Dean Barry R. Bloom and two bioengineers at Harvard, David Edwards and doctoral student Yun-Ling Wong. Prepared by spray drying, a technology used to make powdered milk and other food products, their innovation is a dry-powder preparation of the live attenuated anti-tuberculosis vaccine, bacille Calmette-Guérin (BCG) that can be delivered by aerosol through the mouth or nose to the lungs. BCG is the most widely used vaccine in the world, given annually to more than 100 million children.
Thus far, trials have been limited to guinea pigs, a species highly sensitive to TB, and results indicated that the inhaled vaccine was markedly more effective than the standard injected vaccine. Edwards speculates this is because the inhaled vaccine goes straight to the lungs instead of the bloodstream.
“There is a pressing need for a better TB vaccine,” says Duke University vaccine expert Richard Frothingham. Although we don’t know whether the dry-spray vaccines will be safe in diverse human populations, Frothingham says that needle free delivery and environmental stability are advantages for use in the developing world.