FluMist Nasal Vaccine

June 17 2003 -- The FDA approved FluMist, an influenza vaccine that is the first nasally administered vaccine to be marketed in the United States. It is also the first live virus influenza vaccine approved in the U.S.

FluMist (Influenza Virus Vaccine Live, Intranasal) is approved to prevent influenza illness due to influenza A and B viruses in healthy children and adolescents, ages 5-17 years, and healthy adults, ages 18-49. Children 5-8 years old need two doses at least 6 weeks apart in their first year of influenza vaccination with FluMist, and individuals 9-49 years old need one dose.

According to the Centers for Disease Control and Prevention (CDC), influenza, or "flu," is responsible for an average of approximately 36,000 deaths per year in the United States. Rates of infection are highest among children ages 5-14 years; however the most severe illnesses and deaths occur among individuals with underlying medical conditions, children less than 2 years of age, and those over 65 years old.

"This new vaccine provides another option for protection against influenza and will potentially increase the availability of the injected killed virus vaccine for those people at highest risk," said FDA Commissioner Mark B. McClellan, M.D., Ph.D. "Having enough supplies of flu vaccine available has sometimes been a challenge because there are few manufacturers, the vaccine needs to be changed every year, and certain strains of the virus grow slowly during the vaccine development process."

"In addition, for those people who are eligible for the new vaccine and are reluctant to get a shot, such as healthy children over the age of 5, the availability of FluMist will be especially welcome."

Each dose of FluMist is formulated to contain each of the three influenza virus strains recommended by the U.S. Public Health Service for the 2003-2004 influenza season: two strains of influenza A, which causes the most severe and widespread outbreaks, and one strain of B which usually causes a more mild illness. However, unlike these circulating virus strains, the strains of live virus in the vaccine are modified so they do not grow well at body temperature but replicate enough to induce protective immunity.

In clinical trials, FluMist was evaluated in 20,228 individuals, including over 10,000 healthy children 5-17 years old. The efficacy of the vaccine in preventing influenza was approximately 87 percent among children included in the trial.

In healthy adults ages 18-49 years, FluMist was effective in reducing severe illnesses with fever, and upper respiratory problems which may be caused by influenza infection.

As with other live virus vaccines, FluMist should not be given for any reason to people with immune suppression, including those with immune deficiency diseases, such as AIDS or cancer, and people who are being treated with drugs that cause immunosuppression.

The safety of FluMist in people with asthma or other reactive airway diseases has not been established; FluMist should not be given to people with a history of these problems. In a large safety study, children under five years of age were found to have an increased rate of asthma and wheezing within 42 days of vaccination compared to placebo recipients, and thus FluMist is not recommended for young children. For people age 50 years and over, the safe and effective use of FluMist has also not been established.

FluMist should also not be given to people with chronic underlying medical conditions that may predispose them to severe flu infections. For these people, the injected vaccine is indicated.

People should not receive FluMist, or any other flu vaccine, if they have had an allergic reaction to eggs or to a previous dose of the vaccine.

The most common adverse events associated with the vaccine were nasal congestion, runny nose, sore throat, and cough.

FluMist is manufactured by MedImmune Vaccines Inc., Gaithersburg, Md. It will be marketed by MedImmune and Wyeth, Philadelphia, Pa.

For additional information, please visit the Flu Vaccination Center.

Source: FDA Talkpaper #P03-45, June 17, 2003


Last Editorial Review: 7/7/2004



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