Influenza and children

Influenza infection rates are generally highest in children.68,81,118 Healthy children are also the major cause of the spread of influenza viruses in the community. Vaccination of healthy children has the potential to substantially reduce influenza-like illness and related costs in both the children themselves and their families.

Influenza vaccination recommendations vary between countries. The United States recommends annual vaccination for all persons from 6 months of age.

The United Kingdom influenza vaccination programme includes annual vaccination for all children aged 2–8 years with a live attenuated nasal spray influenza vaccine with the strategy to offer both individual protection and herd immunity. This type of influenza vaccine is expected to be more effective in children but is not currently available in New Zealand.

New Zealand's current strategy

The current New Zealand strategy for children is to offer free influenza vaccination to those with certain medical conditions most likely to lead to serious influenza-related complications.

Children aged 6 months to under 9 years who are receiving the influenza vaccine for the first time should receive two doses four weeks apart. Children who have received a previous influenza vaccination need only a single dose.

Age Funded
vaccine brand
Dose Number
of doses
6–35 months

INFLUVAC® (trivalent)

FLUARIX® TETRA

0.25 mL¥

0.5 mL# 

1 or 2*   

3–8 years

≥ 9 years

INFLUVAC® TETRA 0.5 mL

1 or 2*

1

¥ A half 0.25 mL dose of INFLUVAC® (trivalent) is administered for children aged 6–35 months. This is a different dosage to the FLUARIX® TETRA vaccine dose. Different participant age groups and/or vaccine doses in clinical studies for each brand resulted in different dosage advice.
# A full 0.5 mL dose of FLUARIX® TETRA is administered for children aged 6–35 months.

* Two doses separated by at least four weeks if an influenza vaccine is being used for the first time.

Why does a child aged under 9 years need two doses if being vaccinated for the first time? 

Children under 9 years of age who are receiving influenza vaccine for the first time have a better immune response after two priming doses of vaccine. This may be because they are more likely to be immunologically naive to influenza.

  • Children needing two doses of influenza vaccine:
    • When FLUARIX® TETRA is administered as the first influenza vaccination, one dose of either FLUARIX® TETRA or INFLUVAC® (trivalent) can be given at least 4 weeks later to complete a two-dose priming course.
    • When INFLUVAC® (trivalent) is administered as the first influenza vaccination, a second dose of INFLUVAC® (trivalent) can be given at least 4 weeks later to complete a two-dose priming course.
  • Children who have received one influenza vaccine any time in the past only need a single dose in the current season.

Why does a child aged 6–35 months receive a half 0.25 mL dose of INFLUVAC® or a full 0.5 mL dose of FLUARIX® TETRA?

Different participant age groups and/or vaccine doses in clinical studies for each of these vaccine brands resulted in different dosage advice. The 0.25 mL dose of INFLUVAC® (trivalent) is consistent with the historical recommendations to use a half-dose of influenza vaccine in this age group because the whole cell influenza vaccines used were associated with strong vaccine responses such as fever. An international trend towards the use of quadrivalent influenza vaccines means that clinical studies to change dose recommendations for INFLUVAC® in this age group are unlikely. Therefore, the dosage advice is unlikely to change at this time.

Current influenza vaccines are subunit vaccines that contain only viral surface antigens (haemagglutinin proteins). They are generally well tolerated by children in this age group. However, their ability to induce a robust immune response and protection from influenza is variable.

Receipt of a full 0.5 mL dose of inactivated influenza vaccine has the potential to improve protection against influenza. Clinical studies using a full 0.5 mL dose of the quadrivalent FLUARIX® TETRA vaccine in this age group have been conducted. These studies showed that receiving a full 0.5 mL dose of quadrivalent inactivated influenza vaccine was well tolerated by children in this age group, with vaccine responses comparable to those following either a full dose or a half dose inactivated trivalent influenza vaccine.

Use of paracetamol following vaccination

The routine prophylactic use of paracetamol or any other antipyretic to control fever either prior to or following vaccine administration is not recommended. Evidence shows that the immune response to some antigens can be reduced. However, there is no evidence that this causes individuals to be less protected from disease.

The current recommendations are as follows:

     • Do not use routine prophylactic antipyretics pre- or post-vaccination in the absence of pain or significant discomfort
     • Infants who are uncomfortable with fever should first be managed with appropriate removal of clothing and other cooling measures such as cool drinks
       or tepid sponging
     • Only use analgesics (paracetamol or ibuprofen) for relief of pain or significant discomfort post vaccination

NOTE: treatment advice may differ for other groups.