Flucelvax, new type of flu shot, approved by the Food and Drug Administration

The manufacturing process for the vaccine, called Flucelvax, is similar to the egg-based production method, but the virus strains included in the new vaccine are "grown in animal cells of mammalian origin instead of in eggs," the FDA says.

"The cell-based vaccine is as safe and effective as traditional egg-based vaccine and the technology used to manufacture it is more flexible and reliable than the traditional technology," said Health and Human Services Secretary Kathleen Sebelius in a statement Tuesday.

It is, however, only approved for adults 18 and older, according to the FDA.

The vaccine will not only add to the number of ways to prevent getting the seasonal flu, but provide a weapon should a new flu pandemic emerge.

Even though Flucelvax is the first cell-based flu vaccine approved in the United States, it's been around for five years already. The European Medicines Agency approved the same vaccine, called Optaflu, in 2007.

It's also not the first-ever cell-based vaccine approved in the United States, according to the FDA; polio, smallpox, hepatitis A, rotavirus, rubella, and chickenpox vaccines are produced using cell lines.

The benefit of using the cell-based production method is that is vaccines can be produced much more quickly, within weeks, according to the manufacturer Novartis. Traditional flu vaccine production takes months using specialized eggs.

Having a faster way to manufacture the flu vaccine is especially important when a brand new virus appears that can quickly develop into a pandemic, as seen in 2009 when the H1N1 influenza virus emerged.

That H1N1 pandemic made it even more urgent for health officials to have access to a more quickly produced flu vaccine. Having access to this technology is a big enough deal that the U.S. government has entered into a public/private partnership with the manufacturer, says Dr. William Schaffner, chairman of the Department of Preventive Medicine at Vanderbilt University Medical Center and past president of the National Foundation for Infectious Diseases.

In 2009, a division of HHS joined forces with Novartis to build a state-of-the-art vaccine production facility in Holly Springs, North Carolina, so this cell-based flu vaccine can eventually be manufactured in the United States. That facility is expected to become operational next year.

This is one of three partnerships HHS has established to build facilities that "will use modern cell- and recombinant-based vaccine technologies that have the potential to produce vaccines for not only pandemic influenza but also other threats more quickly and in a more affordable way," according to an HHS statement earlier this year.

While Flucelvax is not produced in eggs, it doesn't automatically mean that it's suited for people with egg allergies; it hasn't been studied in this group of people.

According to FDA spokeswoman Rita Chappelle, the influenza virus reference strains that are adapted for use in manufacturing Flucelvax are obtained from the WHO Collaborating Center, which are grown in eggs. Therefore, she says, "Flucelvax may not be described as completely egg-free."