Vaccine patches may one day retire needles

Flickr/Madmoiselle Lavender

Tiny needles that administer an antimicrobial dose alongside the vaccine when they dissolve in the skin could cut infections from vaccination in developing countries, according to US researchers.

The new micro-needles, which can be applied as a skin patch, use FDA-approved biodegradable polymer materials similar to those used in sutures, which dissolve in the skin within days.

The researchers who developed these micro-needles say that they could prove useful in mass-immunisation campaigns where vaccines are administered quickly and there is a lack of qualified staff.

Although vaccine patches that use micro-needles have been developed before, this time researchers were able to incorporate an antimicrobial agent into the material used to make the needles. This means the patients can be protected against local infection caused by punctured skin at the same time as being immunised.

They said this would also reduce the need for topical antiseptics such as an alcohol swab before administering the vaccine, a stage sometimes omitted in developing countries.

"Vaccines which puncture the skin can create new paths for infection, and the new micro-needle can guard against this," said Roger Narayan, scientist who led the team that developed the needles at the North Carolina State University.

Narayan told SciDev.Net that "antimicrobials provide an extra layer of security, especially in developing countries where healthcare providers have low levels of training".

"The new micro-needles are small coin-sized structures like a band-aid placed on the skin," he said. He added that they could be useful for mass immunisation campaigns in developing countries for routine childhood diseases such as measles, or for situations such as the SARS and swine flu pandemics.

"They are particularly useful in situations where the need is to quickly prepare large numbers of vaccines," particularly in less than sanitary conditions, he added.

Mohga Kamal-Yanni, Oxfam's senior health and HIV policy advisor, said that the ease of application of a skin patch could be an advantage in vaccination programmes. But she added that infection from needles had decreased dramatically with the widespread use of sterilised disposable syringes. 

A spokesperson for international medical organisation Médecins Sans Frontières said hygiene and infection control were important to preventing the spread of viruses. "The lack of qualified healthcare workers is a matter of grave concern in cases such as the flu pandemic," he said.

But the usefulness of such micro-needles would depend on their relative cost, and ability of manufacturers to deliver them in large quantities, he added.