Needle-Free Shots Make Vaccines Less Scary

Sept. 20, 2011 (Chicago) -- If you or your child gets worked up just thinking about getting a flu shot, take note: Needle-free vaccines may soon be coming to your neighborhood -- if they’re not already there.

Needle-free vaccines are generally safer, simple, and more convenient to use, says Bruce Weniger, MD, MPH, associate editor of the journal Vaccine.

And a lot less scary, says Michael Decker, MD, professor of preventive medicine at Vanderbilt University in Nashville, Tenn.

"They let you escape the emotional aspects of that big needle coming right at you," he tells WebMD.

The experts spoke at the 51st Interscience Conference on Antimicrobial Agents and Chemotherapy about a number of skin-based needle-free vaccinations on the market and in development.

Already on the market are new-generation jet injectors, which can be thought of us powerful squirt guns, Weniger says.

PharmaJet is a needle-free system that applies a high-pressure inoculation through the skin. It's being offered as an alternative to traditional flu shots for people who have a fear of needles in many places across the country.

An advantage of the jet injectors is that a smaller dose is needed to achieve inoculation, important for times of vaccine shortage, he says.

Jet injectors can cause momentary discomfort, as they basically punch the skin with a concentrated spray of liquid.

Skin Patch Against Flu

Intercell is working on a vaccine patch for pandemic influenzas, such as the recent outbreak of the avian influenza strain H5N1, or bird flu.

After a dose of injected vaccine is given, the patch is placed over the vaccination site. The patch releases chemicals designed to augment the immune response to the injected vaccine.

"It's put on the skin, much like a Band-Aid. The drug is dissolved into the skin and it's peeled off," Weniger explains.

Like injectors, the patch could expand limited vaccine supplies by allowing fewer or lower doses of vaccine, he says.

A mid-stage study of the patch produced disappointing results last year. It's now being tested in combination with another H5N1 vaccine.

Needles as Thin as Hair

While not needle-free, another new vaccine system uses a needle as thin as a human hair to inoculate people against the flu.

Called Fluzone Intradermal, it's injected into the skin instead of the muscle like traditional flu shots.

"You just put this little cigar-like tube that contains the thin needle up against your arm and pull the plunger," says Decker. He consults for Sanofi-Aventis, which makes both the traditional flu vaccine and this Fluzone.

"It's not quite needle-free but it feels that way to the recipient. You don't get that deep muscle pain associated with traditional flu shots," he says.

Fluzone was licensed by the FDA for use in the 2011-2012 flu season.

Not all the skin-based needle-free vaccines are for the flu. Bioject's experimental Intradermal Pen Injector is being studied as a means of delivering the polio and rabies vaccines.

Its molded syringes have openings about the thickness of a human hair, through which the liquid drug is forced into the skin.

Other groups are pursuing "dissolving microneedles" that disintegrate when they release a dose of the vaccine, Weniger says.

There's a host of advantages to skin-based systems for vaccination, he says. "They’re less dependent on patient cooperation."

Besides skin-based systems for vaccination, certain vaccines are available to be taken by mouth or nasal spray.

These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.