What is the recommended administration route, dosage, and contraindications for Influvac Tetra (influenza vaccine)?

Influvac Tetra Administration

Influvac Tetra should be administered intramuscularly at a dose of 0.5 mL for all individuals aged 6 months and older, with the deltoid muscle preferred for adults and older children, and the anterolateral thigh for infants and young children 1.

Route and Dosage

• Route: Intramuscular (IM) injection only
• Dose volume: 0.5 mL per dose for all age groups ≥6 months 1
• Injection site:
  • Adults and older children: deltoid muscle
  • Infants and young children: anterolateral aspect of the thigh 2, 3

Number of Doses Required

The dosing schedule depends on the child's age and vaccination history:

Children aged 6 months through 8 years:

• 1 dose if they have previously received ≥2 doses of trivalent or quadrivalent influenza vaccine ≥4 weeks apart before the current season (doses do not need to be from the same or consecutive seasons) 2, 3
• 2 doses (≥4 weeks apart) if they have not received ≥2 previous doses or vaccination history is unknown 2, 3

All persons aged ≥9 years:

• 1 dose annually 2

Contraindications

Absolute contraindications include 3:

• History of severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine
• History of severe allergic reaction to a previous dose of any influenza vaccine (egg-based IIV, ccIIV, RIV, or LAIV)

Important note on egg allergy: While a history of severe allergic reaction to egg is a labeled contraindication for egg-based vaccines, ACIP recommends that all persons aged ≥6 months with egg allergy should receive influenza vaccine, and any influenza vaccine (egg-based or non-egg based) that is otherwise appropriate can be used 2, 3.

Precautions

Vaccination should be deferred or carefully considered in 3:

• Moderate or severe acute illness with or without fever
• History of Guillain-Barré syndrome within 6 weeks of receipt of influenza vaccine

Common Pitfalls to Avoid

1. Dose volume confusion: Unlike some other influenza vaccines (Afluria, Fluzone) that have 0.25 mL doses for children aged 6-35 months, Influvac Tetra uses 0.5 mL for all ages 1

2. Two-dose requirement: Children aged 6 months through 8 years who are receiving influenza vaccine for the first time or have not received ≥2 previous doses need 2 doses—missing the second dose leaves them inadequately protected 2, 3

3. Timing: Vaccination should occur as soon as vaccine becomes available in the season, without delay 2