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FluMist Side Effects

Generic Name: influenza virus vaccine, live, trivalent

Note: This page contains information about the side effects of influenza virus vaccine, live, trivalent. Some of the dosage forms included on this document may not apply to the brand name FluMist.

For the Consumer

Applies to influenza virus vaccine, live, trivalent: nasal solution, nasal spray

In 1976, a number of people who received the “swine flu” influenza vaccine developed Guillain-Barré syndrome (GBS), which is a disease that may cause paralysis. Most of these people were over 25 years of age. Although only 10 out of every one million people who received the vaccine actually developed GBS, this number was 6 times higher than would normally have been expected. Most of the people who got GBS recovered completely.

It is assumed that the “swine flu” virus included in the 1976 vaccine caused the problem, but this has not been proven. Since that time, the “swine flu” virus has not been used in influenza vaccines, and there has been no recurrence of GBS that was associated with influenza vaccinations.

In addition to its needed effects, some unwanted effects may be caused by influenza virus vaccine, live, trivalent (the active ingredient contained in FluMist). In the event that any of these side effects do occur, they may require medical attention.

If any of the following side effects occur while taking influenza virus vaccine, live, trivalent, check with your doctor or nurse immediately:

More common:
  • Chills
  • cough
  • decreased appetite
  • fever
  • headache
  • muscle aches
  • sore throat
  • stuffy or runny nose
  • tiredness or weakness
Less common:
  • Earache
  • pain or tenderness around the eyes and cheekbones
  • redness or swelling in the ear
  • shortness of breath or troubled breathing
  • sneezing
  • tightness of the chest or wheezing
  • Difficulty with breathing or swallowing
  • hives
  • itching, especially of the feet or hands
  • reddening of the skin, especially around the ears
  • swelling of the eyes, face, or inside of the nose
  • unusual tiredness or weakness (sudden and severe)
Incidence not known:
  • Anxiety
  • bloody nose
  • blue or pale skin
  • chest pain, possibly moving to the left arm, neck, or shoulder
  • confusion
  • diarrhea
  • dizziness
  • drowsiness
  • fast heartbeat
  • general feeling of illness
  • hoarseness
  • inability to move the arms and legs
  • irritation
  • itching
  • joint pain, stiffness, or swelling
  • nausea
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • severe headache
  • skin rash
  • stiff neck and/or back
  • sudden numbness and weakness in the arms and legs
  • swelling or puffiness of the face
  • unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
  • unusual tiredness or weakness
  • vomiting
  • weakness of the muscles in your face

Severity: Minor

Some of the side effects that can occur with influenza virus vaccine, live, trivalent may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:
  • Abdominal or stomach pain
  • irritability
  • loss of appetite
Incidence not known:
  • Welts

For Healthcare Professionals

Applies to influenza virus vaccine, live, trivalent: nasal spray


Respiratory side effects have frequently included cough, runny nose, and nasal congestion. Otitis media, sneezing, rhinitis, sinusitis, and epistaxis have also been reported.[Ref]

In a clinical trial, among children 6 to 23 months of age, wheezing requiring bronchodilator therapy or with significant respiratory symptoms occurred in 5.9% of FluMist recipients compared to 3.8% of active control (injectable influenza vaccine made by Sanofi Pasteur Inc) recipients (Relative Risk 1.5, 95% CI: 1.2, 2.1). Wheezing was not increased in children 24 months of age and older.[Ref]


Gastrointestinal side effects have frequently included sore throat and vomiting. Abdominal pain and diarrhea have been infrequently reported. Nausea has been reported rarely.[Ref]


Musculoskeletal side effects have frequently included muscle aches.[Ref]


Other side effects have included decreased appetite, irritability, decreased activity, tiredness/weakness, headache, muscle aches, chills, and fever.[Ref]

Nervous system

Nervous system side effects have included Guillain-Barré syndrome, Bell's Palsy, meningitis, eosinophilic meningitis, and vaccine-associated encephalitis. The frequency and/or causal relationship has not been established.[Ref]

An increased frequency of Guillain-Barre syndrome (GBS) was reported in 1976 with the administration of the swine influenza vaccine. Among individuals who received the swine influenza vaccine in 1976, the rate of GBS that exceeded the background rate was <10 cases per 1 million persons vaccinated with the risk for influenza vaccine-associated GBS higher among individuals over 25-years-old compared to individuals younger than 25-years-old. GBS has an annual incidence of 10 to 20 cases per 1 million adults; therefore it is difficult to obtain strong epidemiologic evidence for a possible increase in risk. Investigations, to date, have not reported a substantial increase in the incidence of GBS associated with influenza vaccines (other than the 1976 swine influenza vaccine), and if influenza does pose a risk, it is probably slightly more than 1 additional case per 1 million individuals vaccinated.[Ref]


Dermatologic side effects have included rash.[Ref]


Hypersensitivity reactions have included anaphylaxis, facial edema, and urticaria.[Ref]


Cardiovascular side effects in post-marketing reports have included pericarditis. The frequency and relationship to vaccine exposure has not been determined.[Ref]


1. "Product Information. FluMist (influenza virus vaccine, live, trivalent)." Medimmune Inc, Gaithersburg, MD.

Not all side effects for FluMist may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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