GAITHERSBURG, Md., July 26, 2013 /PRNewswire/ -- MedImmune – the global biologics arm of AstraZeneca – announced today that it began shipping FluMist Quadrivalent to influenza distributors across the United States for the 2013-2014 influenza season. This marks the first shipments of FluMist Quadrivalent, the first and only nasal-spray quadrivalent flu vaccine approved by the Food and Drug Administration (FDA) to help protect against four influenza strains contained in the vaccine: two influenza A strains and two influenza B lineages. All vaccine provided by MedImmune this season in the United States will be FluMist Quadrivalent. The company made the decision to offer quadrivalent vaccine as it provides protection against an additional influenza strain that may circulate during the 2013-2014 influenza season. FluMist Quadrivalent replaces MedImmune's trivalent influenza vaccine, FluMist® (Influenza Vaccine Live, Intranasal). As a needle-free option for eligible individuals and entire families alike (2-49 years of age), FluMist Quadrivalent was developed from the foundation of FluMist. FluMist Quadrivalent is administered as a gentle mist sprayed into the nose, where the influenza virus usually enters the body. The most common side effects of FluMist Quadrivalent are runny or stuffy nose, sore throat, and fever over 100 degrees F. "The introduction of FluMist Quadrivalent reinforces MedImmune's continued commitment to patient health and innovation within the area of infectious disease," said Chris Ambrose, M.D., MedImmune's Vice President of Medical & Scientific Affairs. "MedImmune is one of the first manufacturers to ship quadrivalent vaccine to customers. MedImmune continues to collaborate with healthcare providers, the public health community, and select retail pharmacies to deliver vaccine as early as possible to eligible children and adults." The 2013-2014 influenza season is the first time that quadrivalent influenza vaccines will be available in the United States. Previously, only trivalent influenza vaccines were available, which contained two influenza A strains and one influenza B strain. Since 2001, influenza B strains from two different lineages (B/Yamagata and B/ Victoria) have co-circulated each influenza season in the United States. Trivalent vaccine formulations rely on predictions of which influenza B strains will be dominant in the upcoming season. However, B strain circulation has been difficult to predict correctly, and in 6 of the last 12 flu seasons, the vaccine B strain did not match the dominant circulating B strain. The Centers for Disease Control and Prevention (CDC) recommends everyone 6 months and older get vaccinated against influenza as soon as vaccine is available. The CDC encourages people to get vaccinated each year, regardless of whether or not the viruses in the vaccine have changed since the previous season, because immunity can wane over time. Not all influenza vaccines are approved for all persons. Individuals should check with their healthcare provider regarding eligibility for FluMist Quadrivalent.