New study suggests an oral flu vaccine may be more effective than flu shots.

Results from a new study have added to mounting evidence that an oral flu vaccine may be more effective than flu shots.

Researchers from the International Vaccine Institute in Korea found that administering a certain flu antigen under the tongue of mice prevented the mice from getting infected with many flu viruses, including the avian and swine flu.

The antigen, called matrix protein 2 (M2), has already been found to protect against most strains of the flu and is also contained in the injectable form of the vaccine. Although  flu virus strains change yearly, the M2 protein remains the same in most of viruses, suggesting that the protein could hold the key to developing a universal oral vaccine.

But the protein does not boost lung immunity in the shot the way it does in the experimental oral vaccine.

"It's a fascinating concept in part because this appears to be a valid phenomenon, at least in mice," said Dr. William Schaffner, professor and chair of the Department of Preventive Medicine at Vanderbilt University Medical Center.

"Why it is the oral as opposed to the injection that works is a mystery."

FluMist, an intranasal spray used to deliver the flu vaccine, is the needle-weary person's best alternative to the flu shot. Unlike the oral vaccine, Flu Mist is a live tamed virus that is shot up the nose. The experimental oral vaccine contains only part of the virus.

The findings, published in the November issue of the journal PLoS ONE, suggest that a universal oral flu vaccine may be in the works. If the research translates to humans, it could potentially offer a stronger form of the vaccine, potentially able to withstand some of the changes in the flu strain that occur each year.

But research is still in the early stages.

"While we're waiting for this great new vaccine, let's all get protected with the one we have," said Schaffner.