Influenza viruses are always changing. Each year, the CDC (U.S. Centers for Disease Control and Prevention) updates the flu vaccine to protect against the four seasonal viruses that research suggests will be most common that year.
Because flu viruses – and flu vaccines – are different each year, it’s important to get vaccinated annually. [Learn how to get vaccinated at Cornell]
Flu vaccines are well-tested and meet stringent safety standards. Getting a flu vaccine does not give you the flu, but you may experience mild side effects (see below).
Please consult your physician prior to vaccination if you have: a severe allergy to chicken eggs; had a severe reaction to an influenza vaccination; developed Guillain-Barré syndrome (GBS) within 6 weeks of getting an influenza vaccine previously; or a moderate-to-severe illness with a fever (you should wait until you recover to get vaccinated).
Flu shot – regular dose
When you get a flu shot, inactivated (killed) influenza vaccine is injected by needle, typically into your arm muscle. After vaccination, the antibodies that develop within two weeks will protect you for up to a year.
Side-effects can include soreness, redness or swelling where the shot was given, low-grade fever, aches, and nausea. Getting a flu shot cannot give you the flu.
NOTE: Some inactivated influenza vaccine contains a preservative called thimerosal, which has shown to be safe in vaccines.
Flu shot – high dose (for ages 65+)
Aging can decrease the body's ability to have a good immune response after getting a flu vaccine. Fluzone High-Dose is a higher antigen flu shot designed to give people aged 65 years or older a better immune response, and therefore, better protection against flu than the regular dose flu shot.
Fluzone High-Dose delivery and response is similar to that of the regular-dose flu shot (see above). However, some side effects have been reported more frequently, especially pain, redness, and swelling at the injection site, headache, muscle aches, low-grade fever, and malaise.
The effectiveness of high-dose flu vaccine in comparison with regular-dose vaccine is still being studied. If you have questions about whether Fluzone High-Dose is right for you, please talk with your primary care provider.
FluMist nasal spray
NOTE: per federal public health recommendations, FluMist is NOT available for the 2017-2018 school year.
FluMist is live, attenuated (weakened) influenza vaccine that is sprayed into the nostrils and inhaled. Like the flu shot, it causes an immune response in which antibodies develop that protect you from the flu for up to a year. No preservatives are used in its preparation.
FluMist is an option for people ages 2-49 who do not have asthma or a compromised immune system.
It is NOT appropriate for:
- children younger than 2 and adults 50 years and older (Note: Cornell Health does not provide vaccinations for children)
- pregnant women
- those with a weakened immune system
- those with long-term health problems such as heart disease, kidney or liver disease, lung disease, metabolic disease such as diabetes, asthma, anemia, and other blood disorders
- children younger than 5 years with asthma or one or more episodes of wheezing during the past year
- those with certain muscle or nerve disorders (such as cerebral palsy) that can lead to breathing or swallowing problems
- those in close contact with a person with a severely weakened immune system (requiring care in a protected environment, such as a bone marrow transplant unit)
- children or adolescents on long-term aspirin treatment
Side effects can include cold symptoms (runny nose, headache, sore throat, and cough). Fever is not a common side effect in adults receiving the nasal-spray flu vaccine. In children, side effects can include runny nose, headache, wheezing, vomiting, muscle aches, and fever.
More about flu vaccines
Please refer to the CDC’s flu vaccination resources for more information.