Drug information of Influenza vaccine

Influenza vaccine

Drug group: Vaccines

Influenza Virus Vaccine is a vaccine. It works by stimulating the body to produce antibodies against certain types of the flu virus, which helps your body to fight the infection.

Mechanism of effect

Influenza vaccines induce antibodies against the viral HA in the vaccine, which then blocks viral attachment to human respiratory cells promotes active immunity to avian influenza.


In clinical trials, a 4-fold increase in antibody titers was seen in up to 58% of patients 28 days after second dose.


Onset of Action: Most adults have antibody protection within 2 weeks of vaccination .
Duration of Action: ≥6 to 8 months when vaccine is antigenically similar to circulating virus; response may be diminished in persons ≥65 years and limited evidence suggests titers may decline significantly 6 months following vaccination in this population .


Usual Adult Dose for Influenza Prophylaxis :
0.5 mL, IM, once
Fluzone Intradermal(R) :
0.1 mL, intradermally, once
Usual Pediatric Dose for Influenza Prophylaxis :
6 months to 35 months: 0.25 mL, IM - 1 or 2 doses; if 2 doses, administer 1 month apart
3 to 8 years old: 0.5 mL (1 dose), IM - 1 or 2 doses; if 2 doses, administer 1 month apart
9 years and older: 0.5 mL, IM, once
Comments :
-Previously unvaccinated children (under 9 years of age) should receive 2 doses.
- Check the approved age range for the vaccine being used .
-The deltoid muscle of the upper arm is the preferred administration site.

Drug contraindications

severe hypersensitivity reactions

Side effects

Migraine , Headache , Diarrhea , Wheeziness , Hypertension , Cough , myalgia , Tremor , tiredness , tightness in the chest , stomach pain , Infection , Back pain


Immediate treatment (including epinephrine 1 mg/mL) for anaphylactoid and/or hypersensitivity reactions should be available during vaccine use .
Oculorespiratory syndrome : Oculorespiratory syndrome (ORS) is an acute, self-limiting reaction to IIV with one or more of the following symptoms appearing within 2-24 hours after the dose: Chest tightness, cough, difficulty breathing, facial swelling, red eyes, sore throat, or wheezing. Symptoms resolve within 48 hours of onset .
Syncope : Syncope has been reported with use of injectable vaccines and may result in serious secondary injury (eg, skull fracture, cerebral hemorrhage); typically reported in adolescents and young adults and within 15 minutes after vaccination.
Acute illness : The decision to administer or delay vaccination because of current or recent febrile illness depends on the severity of symptoms and the etiology of the disease. Consider deferring administration in patients with moderate or severe acute illness (with or without fever); vaccination should not be delayed for patients with mild acute illness (with or without fever) .
Bleeding disorders : Use with caution in patients with a history of bleeding disorders (including thrombocytopenia) and/or patients on anticoagulant therapy; bleeding/hematoma may occur from IM administration
Guillain-Barré syndrome : Use with caution in patients with history of Guillain-Barré syndrome (GBS); patients with history of GBS have a greater likelihood of developing GBS than those without .
HIV : Antigenic response may not be adequate in HIV-infected persons with CD4 cells <100/mm3 and viral copies of HIV type 1 >30,000/mL, and a second dose does not improve immune response in these persons .
Neurologic disorders : Some Canadian product labeling recommends delaying therapy in patients with active neurologic disorders .

Points of recommendation

Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:
• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you are allergic to neomycin, polymyxin, rubber, latex, or thimerosal (a preservative)
• if you have a fever, cold, respiratory tract infection, or other infection or recent illness
• if you have a bleeding problem (eg, hemophilia) or low blood platelet levels
• if you have immune system problems (eg, HIV, weakened immune system)
• if you are receiving radiation treatment or chemotherapy, or if you have recently received or will be receiving any other vaccines
• if you have a history of Guillain-barre syndrome or other nervous system problems
Influenza Virus Vaccine is usually given once a year in September, October, or November.
Do not use Influenza Virus Vaccine if it has been frozen, contains particles, is cloudy or discolored, or if the vial or syringe is cracked or damaged.

Pregnancy level


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