(NewsNation) — The Food and Drug Administration has approved an at-home flu vaccine that can be acquired from online pharmacies. FluMist, a nasal spray vaccine produced by AstraZeneca, is approved for and can be self-administered to 2-year-olds up to 49-year-olds. The vaccine, which must be prescribed before purchase, has been available since 2003 for ages 5 to 49 but is now more widely available. It is currently the only self-administered flu vaccine on the market. It may also be given by a health care provider. For at-home use, the vaccine is expected to be available through a third-party online pharmacy, according to a press release. Administered by spraying in the nose, the vaccine contains "a weakened form of live influenza virus strains," the release stated. Is it too early to get a flu shot? "It gives you that little bit of flu exposure which enables you to mount an effective immune response. And it may be an alternative for people who do not want the shot," Dr. Monica Ghandi told "NewsNation Live" on Sunday. "Where it's going to be useful is for children, because they avoid an intramuscular shot. It's not painful, it's super easy, and it's really effective," Ghandi added. Common side effects include fever, runny nose, nasal congestion and sore throat. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said in the release that FluMist "provides a new option for receiving a safe and effective seasonal influenza vaccine potentially with greater convenience, flexibility and accessibility for individuals and families." He added that annual vaccination is "the best way" to prevent the flu.