A novel vaccine delivery device that needs neither refrigeration nor trained practitioners and would cost less than vaccine injections, has been tested in Papua New Guinea, and clinical trials could start next year.
Most vaccines are currently injected using needle and syringe. But unsafe practices including needle and syringe reuse can lead to infections and deaths in developing countries. 
Nanopatch delivers vaccine through an array of microprojections on a tiny patch placed on the skin, so there would be no pain and fears associated with vaccines delivered by needles.
Since skin is rich in immune cells, the device can trigger an immune response and hence protection from disease comparable with that brought about by the needle and syringe method, while requiring only a tiny portion of the dose.
This means that Nanopatch vaccines do not need an adjuvant a substance that is added to the vaccine to increase the body's immune response and are likely to cost much less than conventionally delivered ones.
When the device is made in sufficiently large numbers, our cost estimates are significantly less than US$1 per dose, says researcher Mark Kendall of the University of Queensland, Australia. That opens up possibilities for use in the developing world.
The patches are small and compact, hence easy to transport, and since they use the vaccine in dried form, they do not need cold-chain refrigeration.
Following successful trials against Chikungunya, West Nile virus and the Human Papillomavirus in mice, Nanopatch is now being tested in real-life settings.
As a precursor to full clinical trials, Kendall carried out usability trials last October at the Port Moresby General Hospital in Papua New Guinea.
The devices proved to be easy to use by the healthcare workers with minimal training and were successfully applied onto the patients' arms, Kendall tells SciDevNet.
This means that Nanopatch could go straight to clinical trials, planned for late 2014 to early 2015, he says.
In a separate feat, Roger Narayan, a researcher at the North Carolina State University, United States, developed microneedles that could also be applied as a skin patch.
According to Narayan, Nanopatch will facilitate wider use of vaccines by simplifying delivery and making it more effective, though first the efficacy for each type of vaccine will need to be separately determined.
Although each new vaccine to be delivered through Nanopatch is likely to require new human trials, Kendall says their scope could potentially be reduced once the device's effectiveness is well-established.
Plans for human trials of Nanopatch are due to be funded through a research grant from US pharmaceutical firm Merck and an enterprise award of US$100,000 from Rolex, both received last year.
Nanopatch could be on the market within five to seven years from now, Kendall says.
 The Lancet, doi:10.1016/S0140-6736(09)60632-2 (2009)