H1N1 Information

Vaccine Safety
The 2009 H1N1 influenza vaccine is expected to have a similar safety profile as seasonal flu vaccines, which have a very good safety track record. Over the years, hundreds of millions of Americans have received seasonal flu vaccines.

H1N1 Flu Vaccine: Safety First

Experts describe the process for developing the H1N1 vaccine, testing it in volunteers, and monitoring its safety during and after immunization.


Common Ingredients of U.S. Licensed Vaccines

Influenza A (H1N1) 2009 Monovalent Vaccines Descriptions and Ingredients

WHO: Safety of Pandemic Vaccines

Side Effects
CDC expects that any side effects following vaccination with the 2009 H1N1 influenza vaccine would be rare. If side effects occur, they will likely be similar to those experienced following seasonal influenza vaccine.

Mild Reactions
Severe Reactions

Where the shot was given

•Soreness
•Redness
•Swelling
Life-threatening allergic reactions

•Difficulty breathing
•Hoarseness or wheezing
•Swelling around the eyes or lips
•Hives
•Paleness
•Weakness
•Fast heart beat
•Dizziness

Fainting (mainly adolescents)
Behavior changes

Headache
High fever

Muscle aches
Usually begin within a few minutes to a few hours after the shot

Fever
Seek Medical Attention Right Away

Nausea


Usually begin soon after the shot and last 1-2 days






Questions and Answers on H1N1 Flu Vaccine Safety






Unexpected Adverse Events
The safety of all vaccines licensed in the United States is monitored through a system (Vaccine Adverse Event Reporting System, or VAERS) that collects and analyzes information from adverse events that occur after vaccination. Healthcare providers, vaccine manufacturers, and the general public can submit information to the system via mail, fax, or dedicated Web site, in English or Spanish.

Report a reaction following vaccination




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Monitoring Vaccine Safety
Federal Plans to Monitor Immunization Safety for the Pandemic 2009 H1N1 Influenza Vaccination Program (Federal Immunization Safety Task Force)
Existing vaccine safety monitoring efforts, which have been in place for many years, are being expanded to respond to the 2009 H1N1 influenza. New systems also have been developed to support the vaccine safety monitoring efforts. Details include:

•Large, linked databases from health insurance plans are being matched with state immunization registries to conduct near-real time surveillance of the health outcomes of more than 20 million people following vaccination
•Reporting capacity and staffing has been increased more than 10-fold to collect reports from providers and the public of potential adverse events
•Expanded surveillance systems will enhance detection and follow-up on potential cases of Guillain-Barré syndrome, a rare neurological disorder
•An independent group of experts is being established to conduct regular, rapid reviews of data from federal safety monitoring systems as it accumulates
The Federal Immunization Safety Task Force was established in 2008 to ensure that all federal efforts relevant to immunization safety are coordinated and integrated and that opportunities to enhance synergies across the federal government in immunization safety are identified. This cross-government task force is led by the Department of Health and Human Services and is jointly chaired by the Assistant Secretary for Health and the Assistant Secretary for Preparedness and Response. The Task Force includes participation from the Department of Veterans Affairs and the Department of Defense. All three Departments are responsible for vaccine research and safety monitoring.