Why get vaccinated?
Influenza (“flu”) is a contagious disease that spreads around the United States every year, usually between October and May. Flu is caused by influenza viruses, and is spread mainly by coughing, sneezing, and close contact. Anyone can get flu. Flu strikes suddenly and can last several days. Symptoms vary by age, but can include:
• fever/chills • sore throat
• muscle aches
• runny or stuffy nose
Flu can also lead to pneumonia and blood infections, and cause diarrhea and seizures in children. If you have a medical condition, such as heart or lung disease, flu can make it worse. Flu is more dangerous for some people.
Infants and young children, people 65 years of age and older, pregnant women, and people with certain health conditions or a weakened immune system are at greatest risk. Each year thousands of people in the United States die from flu, and many more are hospitalized. Flu vaccine can:
•keep you from getting flu,
• make flu less severe if you do get it, and
•keep you from spreading flu to your family and other people.
2 Inactivated and recombinant flu vaccines A dose of flu vaccine is recommended every flu season. Children 6 months through 8 years of age may need two doses during the same flu season. Everyone else needs only one dose each flu season.
Some inactivated flu vaccines contain a very small amount of a mercury-based preservative called thimerosal. Studies have not shown thimerosal in vaccines to be harmful, but flu vaccines that do not contain thimerosal are available. There is no live flu virus in flu shots. They cannot cause the flu. There are many flu viruses, and they are always changing. Each year a new flu vaccine is made to protect against three or four viruses that are likely to cause disease in the upcoming flu season.
But even when the vaccine doesn’t exactly match these viruses, it may still provide some protection. Flu vaccine cannot prevent:
• flu that is caused by a virus not covered by the vaccine, or
• illnesses that look like flu but are not.
It takes about 2 weeks for protection to develop after vaccination, and protection lasts through the flu season.