Needle-free vaccines to press flesh - Skin patches being tested to replace shots

Needle-free vaccines to press flesh - Skin patches being tested to replace shots
By Lauran Neergaard
Copyright © 2006, Chicago Tribune and The Associated Press
Published November 7, 2006

GAITHERSBURG, Md. -- Dreaded vaccinations one day could be as simple as sticking on a bandage--ouchless and do-it-yourself.

Early tests of skin-patch vaccines are beginning on hundreds of volunteers, one version designed to protect against the flu and another to prevent travelers' diarrhea.

The idea isn't just pain-free vaccination. The National Institutes of Health is helping to fund the patch research in hopes of strengthening today's imperfect flu shots and gaining extra help if bird flu or some other virus ever triggers a pandemic.

Patch developer Iomai Corp. proposes that the mailman, not a doctor, deliver flu vaccine during a pandemic. Once a vaccine is brewed, simply ship patches to people's homes with instructions to slap one on.

The technology's main promise may be in developing countries. Unlike syringe-based vaccines, patches wouldn't need refrigeration nor pose the infection risk of reused needles.

Only time will tell if the patches really work. Iomai is in initial stages of human testing, and years of additional work are required.

"It may be that the expectations for vaccine patch technology are now slowly bearing fruit," said Dr. William Schaffner of Vanderbilt University, a vaccine expert who has long monitored the field.

If it works against one disease, a patch likely could be tweaked to deliver numerous kinds of vaccines. Iomai also has Defense Department funding to help develop an anthrax vaccine patch.

"The approach is novel and may be the way many vaccines are given in the future," said Dr. Herbert DuPont of the University of Texas Health Sciences Center in Houston. A specialist in diarrheal diseases, he is helping Iomai test the travelers' diarrhea patch on U.S. tourists headed for Mexico.

Most of today's vaccines are shots into muscle. But doctors have long known that getting vaccine just inside the skin is deep enough.

The question is how to do skin vaccination without actually breaking the skin. Patches frequently deliver medications, but drugs are very small molecules that can easily penetrate skin to reach the bloodstream. Vaccines typically contain much larger proteins.

Iomai's method: just get past a thin outer layer of dead skin to the epidermis, the first living skin layer. There, specialized cells can recognize a pathogen and alert the immune system.

In Iomai's laboratory in Gaithersburg, Md., CEO Stanley Erck demonstrates: He brushes his skin with a gadget bearing a bit of sandpaper, like the kind used for filing fingernails. The round patch then is stuck to the scuffed spot for several hours.

"We're not inventing anything new, just exposing pathogens the way humans have seen them all their life," Erck said.

Now come the tests:

- Furthest along are patches designed to protect against an E. coli strain called ETEC, a leading cause of travelers' diarrhea. DuPont's study aims for up to 300 participants to spend at least two weeks in Mexico or Guatemala, visiting specified clinic sites to test the patches.

- Last month, Iomai began first-stage testing of flu vaccine patches on 270 volunteers.

- Another goal is immune-stimulating patches to boost a vaccine's effects. Iomai's travelers' diarrhea patch also seems to give the immune system a general boost. In a small study last year, giving elderly volunteers that patch plus a standard flu shot spurred a greater immune response than the shot alone. The company is preparing a larger study.

"There definitely is promise to that idea," said Dr. David Cho of the NIH's flu product development office, which monitors the patch project--although he says Iomai must prove whether the immune booster works with a variety of flu strains.