A Phase IV, Open Label, Multi-Centre Study to Evaluate the Safety and Tolerability Profile of CSL Limited's Influenza Virus Vaccine in a Paediatric Population Aged >= 6 Months to < 18 Years

Inclusion Criteria:

1. Healthy male or female participants aged ≥ 6 months to < 18 years at the time of vaccination;
2. Written informed consent to participate in the study and adherence to all protocol requirements. Consent will be obtained from the participant, parent or guardian as appropriate according to the applicable Independent Ethics Committee (IEC) and local requirements. Participant assent will also be obtained if required by the applicable IEC;
3. Good health, as determined by medical history, and a targeted physical examination;
4. For participants aged < 9 years, born after a normal gestation period (between 36 and 42 weeks);
5. Females of childbearing potential (defined as having experienced their first menstrual cycle) must be abstinent or be using adequate contraceptive precautions e.g. intrauterine contraceptive device, oral contraceptive, or equivalent hormonal contraception (e.g., progestogen-only implant, vaginal contraceptive ring, cutaneous hormonal patch or injectable contraceptives) for at least 2 months after vaccination. Females aged ≥ 9 years must also return a negative urine pregnancy test at enrolment.

Exclusion Criteria:

1. Known hypersensitivity to a previous dose of influenza vaccine or allergy to eggs, chicken protein, neomycin, polymyxin, or any components of the Study Vaccine;

2. Clinical signs of significant active infection and/or an elevated temperature (≥ 38.0°C oral or ≥ 37.5°C axillary) at study entry;

3. Vaccination against influenza virus in the previous 6 months with a seasonal IVV;

4. Vaccination with an experimental IVV (e.g. a candidate pandemic IVV or a novel IVV) in the previous 6 months;

5. Females of child bearing potential, planning to become pregnant or planning to discontinue contraceptive precautions within 2 months of vaccination;

6. Pregnant or lactating females;

7. Clinically significant medical or psychiatric conditions, as follows:

   • For acute conditions (active or recent), the condition required hospitalisation within the last month; or

   • For chronic conditions: the Investigator feels that the chronic condition is unstable, such as illness exacerbations within the previous month:

     i. requiring hospitalisation; ii. with significant organ function deterioration; iii. with major changes to treatment dosages; iv. requiring major new treatments; or

   • The Investigator feels the participant has a clinical condition that may be adversely affected through study participation.

8. Confirmed or suspected immune deficiency (congenital or acquired, including cancer and human immunodeficiency virus infection);

9. History of seizures, with the exception of a past history of a single seizure event at any age more than two years previously;

10. Known history of Guillain-Barré Syndrome;

11. Current treatment with radiotherapy or cytotoxic drugs, or treatment within the 6 months prior to administration of the Study Vaccine;

12. Current (or within the 90 days prior to receiving the Study Vaccine) immunosuppressive or immunomodulative therapy, including systemic corticosteroids, as follows:

    • Chronic or long term corticosteroids: i. Age less than 9 years: ≥ 0.5 mg/kg/day of oral prednisolone or equivalent daily; ii. Age 9 years and above: ≥ 15 mg/day of oral prednisolone or equivalent daily;

    • Sporadic corticosteroids: i. Age less than 9 years: ≥ 1 mg/kg/day of oral prednisolone or equivalent for 2 or more short courses of > 3 days in the 3 months preceding vaccination; ii. Age 9 years and above: ≥ 40 mg/day of oral prednisolone or equivalent for two or more short courses of > 3 days in the 3 months preceding vaccination; Note: Use of topical or inhalant corticosteroids prior to administration of the Study Vaccine or throughout the Study is acceptable

13. Administration of immunoglobulins and/or any blood products within the 3 months preceding the administration of the Study Vaccine or during the study;

14. Current treatment with warfarin or other anticoagulants;

15. Participation in a clinical trial or use of an investigational compound (i.e. a new chemical or biological entity not registered for clinical use) within 90 days prior to receiving the Study Vaccine or entry into such a study during the on study period;

16. Evidence, or history (within the previous 12 months) of drug or alcohol abuse;

17. If, in the Investigator's opinion, the participant should not take part in the clinical study.