Skin Patches - the Future of Vaccines?

Physicians have traditionally had problems convincing their patients - even the high-risk ones - to get vaccinated, simply because a lot of people are afraid of needles. But there are other problems with injectable vaccines:

- They must be administered by someone with specialized training.

- People must go to their health practitioner to get the vaccine. Since a lot of people can't or won't visit doctors - especially if they have no insurance - it's difficult to "deliver" vaccines to all the people who need them.

- Vaccine solutions must be refrigerated, adding to the delivery problem. If refrigeration fails, the vaccine loses its potency and must be discarded.

- In developing countries, the syringes and needles used to administer vaccines are reused. They're supposed to be sterilized between uses, but if sterilization is incomplete, they could pass along a serious disease like hepatitis or HIV to the next person they're used on.

For a long time it was believed that vaccines needed to injected into muscle tissue in order to be effective. Now, though, physicians have discovered that vaccines can work just as well when they're administered in other ways. For example, a physician has already developed an inhaled flu vaccine, called FluMist. And vaccines can work through the skin if they can just get through the first few layers. This is easily accomplished by "scuffing" the area with mild sandpaper before applying the patch.

Alternative methods of delivering vaccines are important not just because they'll reach more people or decrease the risk of HIV infection. There's also concern about the specific vaccines, like the anthrax vaccine that is mandatory for military personnel who are at risk of attack by biological weapons. The current vaccine, which is divided into six injections given over an 18-month period, has produced some serious side effects. Plus, its sole manufacturer has repeatedly failed FDA inspections, leading to worries about the quality of the vaccine. So the military is highly motivated to support research for other ways to administer the vaccine - or other formulations that aren't as strong but still effective against anthrax.

Right now two vaccines are being tested on humans - one for the flu, and one for travelers' diarrhea. But further research is needed to get the dosage right and be sure vaccines work the way they're supposed to. Eventually many will be tested on humans. But there are a few - the anthrax vaccine included - that are too deadly to test that way, so researchers will have to come up with other ways to be sure those vaccines are effective but not harmful.

Nicotine and birth control patches were just the beginning. Researchers are now realizing the potential of these new ways to administer drugs for disease prevention - with vaccines - as well as treatment.