Flu Shot Vs. Nasal Flu Spray

(CBS/WUSA) -- Debbie Meadows knows that getting the seasonal flu shot can be a lifesaver.

Debbie explains, "I have a son that's had a heart transplant, so I totally get the whole flu shot thing."

Getting vaccinated, most experts agree, is the best way to protect against the flu, but it's not always guarantee.

Dr. Arnold Monto with the University of Michigan School of Public Health explains that, "Flu shots and nasal spray vaccine, they are good vaccines. They're not great vaccines."

Now, a new study shows all vaccines aren't created equal.

When it comes to protecting adults, researchers found the traditional shot to be much more effective than the nasal flu spray.

The study in this month's New England Journal of Medicine looked at about 2,000 healthy adults in the 2007-2008 season and found that flu injections were 68% effective in preventing flu, while the nasal vaccine Flu Mist was 36%.

"The shot was about 50% more effective than the nasal spray vaccine. One reason, the nasal spray may not work as well in adults, because it's made with a live weakened virus that many may have already come in contact with," explains Dr. Monto.

Typically, the flu shot is between 70 and 80 percent effective in younger adults.

How well it works varies every year because scientists make the vaccine before flu season, and they can't always predict which viruses will be circulating.

Health experts still stress vaccination is a must.

"Get the vaccine; that's the best thing we have. The way to prevent flu is to get the vaccine," says Dr. Monto.

Debbie says, "I haven't gotten the flu since I've been taking the flu shot."

For Debbie, she explains, it has always protected her and her family.