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Vaccines, Blood & Biologics

Influenza A (H1N1) 2009 Monovalent Vaccine Safety Monitoring

September 15, 2009

On September 15, 2009, FDA licensed (approved) vaccines from four different manufacturers to protect against the 2009 H1N1 influenza virus.  The Influenza A (H1N1) 2009 Monovalent vaccines are made from a single influenza virus strain that is an A/California/7/09-like virus.

FDA approved these vaccines as a strain change to each manufacturer’s seasonal influenza vaccine.  There is considerable experience with seasonal influenza vaccine development and production, and influenza vaccines produced by this technology have a long and successful track record of safety and effectiveness in the United States.  The Influenza A (H1N1) 2009 Monovalent vaccines will undergo the usual testing and lot release procedures that are in place for seasonal influenza vaccines.

The expected side effects will be similar to those of the seasonal influenza vaccine, potentially including a mild fever, body aches, and fatigue for a few days after the vaccine, and soreness at the injection site.  The most common side effects seen with administration of the nasal vaccine include runny nose or nasal congestion in recipients of all ages, fever more than 100 degrees Fahrenheit in children two to six years of age, and sore throat in adults.  As with any medical product, serious adverse events may occur.  People who have a severe (life-threatening) allergy to chicken eggs or to any other substance in the vaccine should not be vaccinated.

FDA and CDC will closely monitor the safety of the Influenza A (H1N1) 2009 vaccines.  FDA is collaborating with CDC, HHS, and other government agencies to enhance the capacity for adverse event safety monitoring during and after the Influenza A (H1N1) 2009 vaccination program.  Efforts are underway to establish a robust network to share information in real-time.  The network will build on the well established Vaccine Adverse Event Reporting System and Vaccine Safety Datalink by integrating capabilities from the Department of Defense, the Department of Veterans Affairs, the Center for Medicare and Medicaid Services, State, Territorial, Tribal, and local public health and medical, and private sector healthcare entities.  FDA is also engaged with international regulatory partners on pharmacovigilance planning efforts.

The purpose of the collaborations is to improve our ability to identify adverse events following receipt of the 2009 H1N1 monovalent vaccines and rapidly evaluate them to determine their significance.

CDC has posted information on its web site regarding H1N1 safety monitoring (  The information outlines the objectives of the 2009 H1N1 monovalent vaccine safety monitoring response:

  • Timely identification of clinically significant adverse events following receipt of 2009 H1N1 monovalent vaccine
  • Rapid evaluation of serious adverse events after 2009 H1N1 monovalent vaccine to determine the public health importance
  • Evaluation of the risk of Guillian-Barre syndrome (GBS) associated with the 2009 H1N1 monovalent vaccine.

Contact FDA

(800) 835-4709
(240) 402-8010
Consumer Affairs Branch (CBER)

Division of Communication and Consumer Affairs

Office of Communication, Outreach and Development

Food and Drug Administration

10903 New Hampshire Avenue

Building 71 Room 3103

Silver Spring, MD 20993-0002

Page Last Updated: 01/22/2015
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