A Clinical Study of Pre and Post Vaccination Serology in Children Receiving the Seasonal Southern Hemisphere Formulation of Inactivated Influenza Vaccine

A total of 40 children (aged between 6 months and 9 years of age) will be enrolled into this research study. After written and informed parental consent, a 3ml blood sample will be collected to determine the baseline anti-haemagglutination antibody titre. The participant will then be administered the Licensed Quadrivalent Seasonal Influenza vaccine according to the Australian Immunisation Handbook (AIH) guidlines. At the last visit, a second 3ml blood sample will be collected for the determination of post-vaccination antibody titres. All participants will receive an intramuscular injection of the seasonal licensed southern hemisphere seasonal influenza vaccine according to the Australian Immunisation Handbook recommendation. The World Health Organisation (WHO) provides a recommendation for the composition of the Southern Hemisphere influenza virus vaccines. For Children aged 6 months to up to 3 years of age FluQuadri Junior- Sanofi-Aventis Australia Pty Ltd (quadrivalent inactivated influenza virus). Each 0.25mL pre-filled syringe contains 7.5µg haemagglutinin of each of the four recommended influenza virus strains; 50µg formaldehyde; 125µg octoxinol 9; 0.5µg ovalbumin. For Children aged 3 years of age and older FluQuadri – Sanofi-Aventis Australia Pty Ltd (quadrivalent inactivated influenza virus). Each 0.5 mL pre-filled syringe contains 15 µg haemagglutinin of each of the four recommended influenza virus strains; 100 µg formaldehyde; 250 µg octoxinol 9; 1 µg ovalbumin. According to the Australian Immunisation Handbook, children aged 6 months to <9 years receiving influenza vaccine for the first time require two doses, at least 4 weeks apart, to maximize the immune response to vaccine strains. For children who have previously received 1 or more doses of trivalent or quadrivalent influenza vaccine, only 1 dose of influenza vaccine is required in the current season and all seasons thereafter. Therefore participants in the study will receive either 1 or 2 doses of the quadrivalent influenza vaccine depending on whether they have ever received a prior influenza vaccine. The duration of the study for each participant will be approximately 1-2 months, during which time they will be asked to: • Attend up to three clinic visits at the Women’s and Children’s Hospital with a duration of up to 30 minutes. • Receive a licensed seasonal influenza vaccine • Have 2 blood samples taken (3ml) prior to and approximately 21 days after vaccination The following study activities will occur as described below: Visit 1 (Day 0 of the study) Duration: 30 minutes Consent process Questions on age, gender, address, contact details, medical history, previous vaccinations and medications. Blood draw (3ml). Vaccination: Licensed Seasonal Influenza vaccine (quadrivalent) Observation period for 15 mins after vaccination Please note: children who have never received an influenza vaccine prior to participating in this study will require a third visit for a second dose of influenza vaccine 4 weeks after their first dose to maximise protection against influenza infection. Children who have previously been vaccinated with the seasonal influenza vaccine in previous years will only require 1 dose of the vaccine. Visit 2 (for participants who have not had a prior influenza vaccine) Duration: 30 minutes Vaccination: Licensed Seasonal Influenza vaccine (quadrivalent) Observation period for 15 mins after vaccination Final visit (21+ 4 days post vaccination) Duration: approx 15 min Blood draw (3ml) The study staff will ask questions about the participants health and illness (eg any confirmed influenza infections during the study period).