Trivalent/Quadrivalent Injection (flu shot) Vaccine Type | Usage | Precautions | Side Effects

Trivalent/Quadrivalent Injection (flu shot) Vaccine Type | Usage | Precautions | Side Effects

  • Influenza (flu) is caused by Influenza viruses (Type A, Type B and Type C), all are RNA viruses of the Orthomyxoviridae family.
  • Type A and Type B cause most of the cases. Type C is relatively less common and causes mild disease.
  • Seasonal outbreaks occurring in the winter season are a hall-mark of this potentially deadly disease.

Vaccine Type

  • Injection: inactivated virus vaccine
  • Nasal Spray: Live-attenuated vaccine

Available as

  • Trivalent/Quadrivalent Injection (flu shot): Trivalent provides immunity against two strains of
    Type A, and one strain of Type B virus. Quadrivalent provides immunity against two
    strains of Type A and two Type B viruses.
  • Nasal Spray: Two Type A and two Type B strains.
  • (Virus strains covered by the vaccine may differ from season to season depending upon CDC recommendations for a particular season.)


  • Vaccine effectiveness differs from season to season. While no concrete
    figures are available because of the wide differences in response among the
    population, studies have shown that the vaccine are effective in decreasing
    the incidence of new cases and reducing influenza-related hospital admissions.


  • Every one older than 6 months age should be vaccinated, every season.
  • Two doses are required for children aged 6 months to 8 years who have not been
    previously vaccinated or received only one dose of the vaccine. The two doses should be given at least 28 days apart.
  • Persons aged 6 months to 8 years who were vaccinated with two doses previously usually require single dose.
  • Persons aged 9 years or older usually need a single dose.
  • Injection: for use in any one aged 6 months or older.
  • Nasal Spray: for persons aged 2 years to 49 years.


All Influenza vaccines are contra-indicated in:

  • Children younger than 6 months.
  • People with allergies to any component of the vaccine.
  • Patients with egg allergy should not receive vaccines which have egg protein as their ingredients.

Contraindications specific to Nasal Spray vaccine:

  • People younger than 2 years and older than 49 years.
  • Pregnant women.
  • Those who have taken antiviral medication in the last 48 hours.
  • Patients with some chronic conditions like cardiovascular diseases, diabetes mellitus, and immunodeficient individuals.
  • Children aged 2-17 years who are taking Aspirin.

Other Precautions:

  • Children with Asthma may experience increased sneezing.
  • Vaccination may be differed in acutely ill persons until they are well.
  • Patients with a history of Guillain-Barre Syndrome may be advised not to take the vaccine.