Influenza vaccine can prevent influenza (flu).
Flu is a contagious disease that spreads around the United States every year, usually between October and May. Anyone can get the flu, but it 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 of flu complications.
Pneumonia, bronchitis, sinus infections and ear infections are examples of flu-related complications. If you have a medical condition, such as heart disease, cancer or diabetes, flu can make it worse.
Flu can cause fever and chills, sore throat, muscle aches, fatigue, cough, headache, and runny or stuffy nose. Some people may have vomiting and diarrhea, though this is more common in children than adults.
Each year thousands of people in the United States die from flu, and many more are hospitalized. Flu vaccine prevents millions of illnesses and flu-related visits to the doctor each year.
CDC recommends everyone 6 months of age and older get vaccinated every flu season. Children 6 months through 8 years of age may need 2 doses during a single flu season. Everyone else needs only 1 dose each flu season.
Live, attenuated influenza vaccine (called LAIV) is a nasal spray vaccine that may be given to non-pregnant people 2 through 49 years of age.
It takes about 2 weeks for protection to develop after vaccination.
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. Even when the vaccine doesn't exactly match these viruses, it may still provide some protection.
Influenza vaccine does not cause flu.
Influenza vaccine may be given at the same time as other vaccines.
Tell your vaccine provider if the person getting the vaccine:
Is younger than 2 years or older than 49 years of age.
Is pregnant.
Has had an allergic reaction after a previous dose of influenza vaccine, or has any severe, life-threatening allergies.
Is a child or adolescent 2 through 17 years of age who is receiving aspirin or aspirin-containing products.
Has a weakened immune system.
Is a child 2 through 4 years old who has asthma or a history of wheezing in the past 12 months.
Has taken influenza antiviral medication in the previous 48 hours.
Cares for severely immunocompromised persons who require a protected environment.
Is 5 years or older and has asthma.
Has other underlying medical conditions that can put people at higher risk of serious flu complications (such as lung disease, heart disease, kidney disease, kidney or liver disorders, neurologic or neuromuscular or metabolic disorders).
Has had Guillain-Barré Syndrome within 6 weeks after a previous dose of influenza vaccine.
In some cases, your health care provider may decide to postpone influenza vaccination to a future visit.
For some patients, a different type of influenza vaccine (inactivated or recombinant influenza vaccine) might be more appropriate than live, attenuated influenza vaccine.
People with minor illnesses, such as a cold, may be vaccinated. People who are moderately or severely ill should usually wait until they recover before getting influenza vaccine.
Your health care provider can give you more information.
Runny nose or nasal congestion, wheezing and headache can happen after LAIV.
Vomiting, muscle aches, fever, sore throat and cough are other possible side effects.
If these problems occur, they usually begin soon after vaccination and are mild and short-lived.
As with any medicine, there is a very remote chance of a vaccine causing a severe allergic reaction, other serious injury, or death.
An allergic reaction could occur after the vaccinated person leaves the clinic. If you see signs of a severe allergic reaction (hives, swelling of the face and throat, difficulty breathing, a fast heartbeat, dizziness, or weakness), call 9-1-1 and get the person to the nearest hospital.
For other signs that concern you, call your health care provider.
Adverse reactions should be reported to the Vaccine Adverse Event Reporting System (VAERS). Your health care provider will usually file this report, or you can do it yourself. Visit the VAERS website at
The National Vaccine Injury Compensation Program (VICP) is a federal program that was created to compensate people who may have been injured by certain vaccines. Visit the VICP website at
Ask your health care provider.
Call your local or state health department.
Contact the Centers for Disease Control and Prevention (CDC):
Call 1-800-232-4636 (1-800-CDC-INFO) or
Visit CDC's influenza website at
Vaccine Information Statement
Live Attenuated Influenza Vaccine
8/15/2019
42 U.S.C. § 300aa-26
Department of Health and Human Services
Centers for Disease Control and Prevention
Many Vaccine Information Statements are available in Spanish and other languages. See
Hojas de información sobre vacunas están disponibles en español y en muchos otros idiomas. Visite
Source: Centers for Disease Control and Prevention AAP Feed run on: 9/23/2024 Article information last modified on: 8/8/2023