Seasonal influenza vaccine protects against three strains of influenza, including the 2009 H1N1 influenza virus, which caused the 2009 pandemic. Last year because the 2009 H1N1 virus emerged after production began on the seasonal vaccine,  two separate vaccines were needed to protect against seasonal flu and the 2009 H1N1 pandemic flu virus, but this year, only one vaccine is necessary.

According to the Centers for Disease Control and Prevention (CDC), between 5 and 20 percent of the U.S. population develops influenza each year, leading to more than 200,000 hospitalizations from related complications and about 36,000 deaths.

"The best way to protect yourself and your family against influenza is to get vaccinated every year," said Karen Midthun, M.D., acting director of FDA's Center for Biologics Evaluation and Research. "The availability of a new seasonal influenza vaccine each year is an important tool in the prevention of influenza related illnesses and death."

In addition to the important role that health care providers play in recommending influenza vaccination for their patients, influenza vaccination of health care personnel is important to protect themselves, their patients, their family, and the community from influenza. FDA urges health care organizations to encourage their members to get vaccinated.

The brand names and manufacturers for the upcoming season's vaccines are: Afluria, CSL Limited; Agriflu, Novartis Vaccines and Diagnostics; Fluarix, GlaxoSmithKline Biologicals; FluLaval, ID Biomedical Corporation; FluMist, MedImmune Vaccines Inc.; Fluvirin, Novartis Vaccines and Diagnostics Limited; and Fluzone and Fluzone High-Dose, Sanofi Pasteur Inc.

Each year, experts from FDA, World Health Organization, CDC, and other institutions study virus samples and patterns collected worldwide to identify strains likely to cause the most illness during the upcoming season.

Based on that information and the recommendations of FDA's Vaccines and Related Biological Products Advisory Committee, manufacturers included the respective three strains in the 2010-2011 vaccines. The closer the match between the circulating strains and the strains in the vaccine, the better the protection against influenza disease.

Vaccines for the 2010-2011 seasonal influenza contain the following strains:

·    A/California/7/09 (H1N1)-like virus (pandemic (H1N1) 2009 influenza virus)

·    A/Perth /16/2009 (H3N2)-like virus

·    B/Brisbane/60/2008-like virus

There is always a possibility of a less than optimal match between the virus strains predicted to circulate and the virus strains that end up causing the most illness.  However, even if the vaccine and the circulating strains are not an exact match, the vaccine may reduce the severity of the illness or may help prevent influenza-related complications.

Seasonal influenza vaccines have a long and successful track record of safety and effectiveness in the United States.

The labeling for one vaccine, CSL Limited's Afluria, has undergone changes this season to inform health care providers about an increased incidence of fever and febrile seizure, which was seen in young children, mainly those younger than 5 years, following administration of the 2010 Southern Hemisphere formulation of CSL's influenza vaccine. The Southern Hemisphere influenza season occurs prior to that of the Northern Hemisphere. CSL Limited will not be supplying the United States with the 0.25 milliliter single-dose, prefilled syringes, which are used in very young children. The 0.5 milliliter single-dose, prefilled syringes and 5 milliliter multi-dose vials will be distributed.

FDA is requiring CSL Limited to conduct a study of Afluria in children to obtain additional information regarding the febrile events that were seen in the Southern Hemisphere.

The Centers for Disease Control and Prevention has published recommendations for annual influenza vaccination to include all people aged 6 months and older. The expanded recommendation is to take effect in the 2010-2011 influenza season. The Advisory Committee on Immunization Practices (ACIP), which advises the CDC on vaccine issues, voted on the new recommendation during its February 24, 2010 meeting in Atlanta. Prior recommendations for seasonal influenza vaccination focused on vaccination of persons at increased risk for complications from influenza including people with underlying health conditions, children 6 months through 18 years of age, and close contacts of high risk persons among others.  The new recommendations can be found at http://www.cdc.gov/mmwr/preview/mmwrhtml/rr59e0729a1.htm.

For more information:

FDA Web Page on Influenza Vaccine Safety & Availability

http://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/VaccineSafety/ucm110288.htm

FDA List of Strains Included in the 2010-2011 Influenza Vaccine

http://www.fda.gov/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Post-MarketActivities/LotReleases/ucm202750.htm

U.S. Centers for Disease Control and Prevention Web Page on Seasonal Influenza

http://www.cdc.gov/flu/

SOURCE U.S. Food and Drug Administration