Influenza virus vaccine, h1n1, inactivated Side Effects
Medically reviewed by Drugs.com. Last updated on Dec 27, 2023.
Applies to influenza virus vaccine, h1n1, inactivated: intramuscular suspension.
Warning
The injectable H1N1 influenza virus vaccine is a "killed virus" vaccine. H1N1 influenza virus vaccine is also available in a nasal spray form, which is a "live virus" vaccine. This medication guide addresses only the injectable form of this vaccine.
H1N1 influenza is sometimes called "swine flu" because it is usually found in pigs. You cannot become infected with H1N1 influenza from eating pork products.
The injectable form of H1N1 influenza virus vaccine is a "killed virus" vaccine and will not cause you to become ill with the flu virus that it contains. However, you may have flu-like symptoms at any time during flu season that may be caused by other strains of influenza virus.
Do not receive this vaccine if you have ever had an allergic reaction to a flu vaccine, or if you are allergic to eggs.
Before you receive an H1N1 influenza virus vaccine, tell your doctor if you have a weak immune system, or a history of Guillain-Barré syndrome or neurologic disorder affecting the brain (especially if these were caused by a vaccine).
You can still receive an H1N1 influenza vaccine if you have a cold or fever. In the case of a more severe illness with a fever or any type of infection, wait until you get better before receiving this vaccine.
Keep track of any and all side effects you have after receiving this vaccine. If you ever have to receive another influenza virus vaccine in the future, you will need to tell the doctor if the first shot caused any side effects.
Like any vaccine, H1N1 influenza virus vaccine may not provide protection from disease in every person. This vaccine will not prevent illness caused by avian flu ("bird flu").
Becoming infected with influenza is much more dangerous to your health than receiving the vaccine to protect against it. Most people with H1N1 influenza have recovered, but the virus has caused some deaths.
The injectable form of H1N1 influenza virus vaccine is a "killed virus" vaccine and will not cause you to become ill with the flu virus that it contains. However, you may have flu-like symptoms at any time during flu season that may be caused by other strains of influenza virus.
You should not receive a booster vaccine if you had a life-threatening allergic reaction after the first shot.
Keep track of any and all side effects you have after receiving this vaccine. If you ever have to receive another H1N1 influenza virus vaccine in the future, you will need to tell the doctor if the first shot caused any side effects.
Get emergency medical help if you have any of these signs of an allergic reaction while taking influenza virus vaccine, h1n1, inactivated: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
-
weakness, numbness or tingly feeling in your feet and spreading upward;
-
problems with vision, speech, swallowing, or bladder and bowel functions;
-
severe lower back pain;
-
slow heart rate, trouble breathing, feeling like you might pass out;
-
high fever; or
-
unusual bruising or bleeding.
Less serious side effects can last a day or two after you receive this vaccine and may include:
-
runny or stuffy nose;
-
low fever;
-
sore throat;
-
loss of appetite;
-
headache, tired feeling; or
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
For Healthcare Professionals
Applies to influenza virus vaccine, h1n1, inactivated: intramuscular suspension.
General
The most common adverse events were soreness at the injection site lasting less than 2 days, and local pain and swelling.[Ref]
Local
Very common (10% or more): Soreness at vaccination site lasting under 2 days (64%)
Frequency not reported: Local pain and swelling[Ref]
Nervous system
Frequency not reported: Headache, Guillain-Barre Syndrome, convulsions, myelitis (including encephalomyelitis and transverse myelitis), facial palsy (Bell's palsy), optic neuritis/neuropathy, brachial neuritis, syncope (shortly after vaccination), dizziness, paresthesia[Ref]
Hypersensitivity
Postmarketing reports: Anaphylaxis, other allergic/hypersensitivity reactions (including urticaria, angioedema)[Ref]
Dermatologic
Postmarketing reports: Stevens-Johnson syndrome, pruritus[Ref]
Respiratory
Postmarketing reports: Dyspnea, pharyngitis, rhinitis[Ref]
Musculoskeletal
Frequency not reported: Myalgia[Ref]
Hematologic
Postmarketing reports: Thrombocytopenia, lymphadenopathy[Ref]
Other
Frequency not reported: Fever, malaise
Postmarketing reports: Pain, asthenia/fatigue, pain in extremities, chest pain[Ref]
Cardiovascular
Postmarketing reports: Vasculitis, vasodilation/flushing[Ref]
More about influenza virus vaccine, h1n1, inactivated
- Check interactions
- Compare alternatives
- Dosage information
- During pregnancy
- FDA approval history
- Drug class: viral vaccines
Patient resources
- Influenza A (H1N1) 2009 Monovalent Vaccine drug information
- Influenza a virus vaccine, h1n1, inactivated (Advanced Reading)
Related treatment guides
References
1. Product Information. Influenza Virus Vaccine, H1N1, Inactivated (influenza virus vaccine, H1N1, inactivated). CSL Biotherapies. 2022.
Further information
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.
