NCT03330132

Immunogenicity of Alternative Annual Influenza Vaccination Strategies in Older Adults in Hong Kong

Immunogenicity of Alternative Annual Influenza Vaccination Strategies in Older Adults in Hong Kong - a Randomized Controlled Trial

• Status: Active Not Recruiting
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 1,861 (actual)
• Sponsor: The University of Hong Kong · Academic / Other
• Sex: All
• Age: 65 Years – 82 Years
• Healthy volunteers: Accepted

Summary

This study allows to evaluate the strength and duration of immune responses between annual receipt of standard inactivated vaccine and alternative potent vaccines, including annual receipt of adjuvanted inactivated vaccine, annual receipt of high-dose inactivated vaccine, annual receipt of recombinant HA vaccine, and the alternate combinations of the former three vaccines over four years, for identifying improved vaccination strategies for influenza vaccination in older adults in a location experiencing a subtropical pattern in influenza activity.

Detailed description

Background: The typical vaccination strategy of annual administration with inactivated trivalent influenza vaccine (TIV) or quadrivalent influenza vaccine (QIV) may provide suboptimal protection to older adults in a location with prolonged periods of influenza activity because of the weaker immune response of older adults to vaccination and because of post-vaccination waning in protection over the course of a year. We hypothesize that in a subtropical or tropical location with prolonged circulation of influenza viruses, the higher antibody titers over years achieved after receipt of annual high-dose vaccine, MF59-adjuvanted vaccine or recombinant haemagglutinin (HA) vaccine, or different vaccination strategies of their combinations with or without the standard vaccine, might lead to greater protection than annual receipt of standard vaccines. Aim: To test the immune profiles over time of older adults following different influenza vaccination strategies. Design and subjects: Initially a 4-year immunogenicity study with a randomized controlled design among 2200 older adults aged 65-82 years. We will enroll participants who are willing to receive annual influenza vaccination from the general community including community centres and day-care centres. Eligible individuals will be randomly allocated to ten intervention groups (i.e. annual standard QIV, annual MF59-adjuvanted TIV, annual high-dose TIV, annual recombinant-HA QIV, and six combinations of their alternate annual use) consisting of four rounds of vaccination before each winter influenza season and followed up for 4 years. For each round of vaccination, blood samples for immunological tests will be collected before vaccination and 30 and 182 days after vaccination in all participants, and also at 7, 91 and 273 days after vaccination in a subset of 10% of the participants. Acute illnesses among participants will be monitored by active surveillance efforts during influenza seasons. The vaccine formulation in each round of vaccination will be updated for each season according to WHO recommendations. Study extension: In years 5-8, all participants will receive the recombinant-HA QIV once per year before each winter influenza season, and their receipt of COVID-19 vaccines will also be recorded. Samples will be collected at the same timepoints to monitor immune responses to influenza vaccination and how responses are affected by prior vaccination history. Main outcome measures: Antibody titers measured by haemagglutination-inhibition assays, which is an established correlate of protection, in addition to other measurements on humoral and cell-mediated immune responses in the ten intervention groups each year.

Conditions

• Influenza, Human

Interventions

Type	Name	Description
BIOLOGICAL	Standard inactivated influenza vaccine (NH formulation)	0.5mL FluQuadri®, Sanofi Pasteur, containing 60μg antigen - 15μg for each influenza strain included - with strains recommended by the WHO for the northern hemisphere formulation.
BIOLOGICAL	MF 59 adjuvanted inactivated influenza vaccine (NH formulation)	0.5mL FLUAD(TM), Seqirus containing 45μg antigen; 15μg for each influenza strain included and MF59C.1 adjuvant (MF59®) with strains recommended by the WHO for the northern hemisphere formulation.
BIOLOGICAL	High-dose inactivated influenza vaccine (NH formulation)	0.5mL Fluzone® High-Dose, Sanofi Pasteur containing 180μg antigen; 60μg for each influenza strain included with strains recommended by the WHO for the northern hemisphere formulation.
BIOLOGICAL	Recombinant hemagglutinin inactivated influenza vaccine (NH formulation)	0.5mL Flublok®, Protein Sciences Corporation containing 180μg antigen, 45μg for each influenza strain included with strains recommended by the WHO for the northern hemisphere formulation.

Timeline

• Start date: 2017-10-07
• Primary completion: 2025-12-01
• Completion: 2026-12-01
• First posted: 2017-11-06
• Last updated: 2023-12-11

Locations

1 site across 1 country: China