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A Nasal Spray Flu Vaccine

FluMist is a licensed nasal spray flu vaccine that may offer several potential advantages over the flu shot. FluMist is based on live influenza viruses that have been weakened (attenuated) so they can't cause the flu. Because the FluMist vaccine contains live viruses, it may stimulate a broader immune response than the current vaccine, which contains proteins from inactivated, or "killed" viruses. The live vaccine viruses also have been selectively grown in the lab over many generations at increasingly cooler temperatures. This "cold adaption" is a double safety measure, preventing the viruses from spreading beyond the relatively cool upper respiratory tract. Finally, the FluMist vaccine is administered as a spray into the nose, which adults and especially children say is more pleasant than getting the current flu shot.

The National Institute of Allergy and Infectious Diseases (NIAID) has a long history of working to develop the live influenza vaccine and continues to support clinical studies using FluMist. The timeline below shows FluMist's developmental milestones and its progress toward approval by the Food and Drug Administration.

Winter 2003–2004

FluMist is available for use for the first time to health adults and children ages 5 through 49.

June 2003

The FDA approves FluMist for healthy adults and children ages 5 through 49.

December 2002

The FDA's Vaccines and Related Biological Products Advisory Committee again evaluates the safety and efficacy of FluMist. The committee recommends that the FDA approve FluMist for healthy children and adults ages 5 through 49. MedImmune continues to work with the FDA to answer the committee's questions about the safety and efficacy of FluMist for children under 5 and adults 50 and older.

January 2002

MedImmune, Inc. acquires FluMist when it purchases Aviron.

July 2001

The FDA's Vaccines and Related Biological Products Advisory Committee evaluates the safety and efficacy of FluMist. The majority of the committee members agree that while there are adequate data to show the vaccine works in healthy people ages one to 64, the analysis of the safety data is incomplete. Aviron continues to work with the FDA to provide additional clinical and manufacturing data to support the licensing of FluMist.

October 2000

Aviron submits an application for FluMist to the Food and Drug Administration (FDA), seeking approval for FluMist as an annual vaccine for healthy individuals one to 64 years old.


Aviron enters an agreement with Wyeth Lederle Vaccines of Philadelphia for marketing FluMist in the United States and worldwide.


The NIAID sponsors a large, multiyear trial with FluMist to test a popular theory: If a critical number of children, about 70 percent, are vaccinated against influenza, the spread of the virus within a community can be stopped, resulting in a kind of "community immunity." In Temple, Texas, researchers vaccinate more than 14,000 children with FluMist over the next several years. When this ongoing study finishes, researchers will compare influenza-associated illness rates in Temple with those in similarly sized communities without FluMist vaccine. In 2003, researchers conduct data-analysis by comparing influenza-associated illness rates in Temple with those in similarly sized communities without FluMist vaccine.


NIAID's Vaccine Treatment and Evaluation Units begin studies to evaluate the safety of FluMist in HIV-positive adults and children.

1997–98 flu season

The vaccine proves similarly effective in the same children against the influenza strains included in the vaccine. In addition, an unanticipated new influenza strain emerges this season. FluMist proves 86 percent effective in protecting children against this emergent strain that is not contained in the vaccine. FluMist also provided 94 percent protection against influenza-related middle-ear infections, or otitis media.

1996–97 flu season

NIAID's Vaccine Treatment and Evaluation Units and Aviron perform a pivotal Phase III efficacy study that finds the vaccine 93 percent effective in preventing influenza in children aged 15 to 71 months.


NIAID signs a cooperative research and development agreement with Aviron of Mountain View, California, to continue studying the safety, efficacy, and immunogenicity of FluMist in various populations.


NIAID sponsors a series of clinical studies to evaluate the safety, efficacy, and dosage of the live, cold-adapted, attenuated flu vaccine.


Brian Murphy, M.D., and other NIAID researchers at the Laboratory of Infectious Diseases take over the lead in developing the live, attenuated flu vaccine.


Dr. Hunein Maassab of the University of Michigan develops a live, cold-adapted flu virus for use in a vaccine.


The U.S. Army supports research at the University of Michigan to develop a live, attenuated influenza vaccine strategy.


A pandemic caused by the H2N2 influenza virus results in more than 69,000 deaths in the United States, underscoring the need for new strategies to prevent the flu.

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Last Updated December 04, 2006