The immune response to 6-monthly versus annual standard dose inactivated trivalent influenza vaccination in older people: study protocol for a randomised clinical trial.
The seasonal influenza vaccine is less effective in older people and a single dose is unlikely to provide the year-round protection necessary for tropical climates which have year-round influenza virus activity. This study aims to assess the effect of a trivalent inactivated influenza vaccine (IIV3) booster at 180 days on haemagglutination-inhibition (HI) antibody titres for each of the influenza strains present in the administered vaccine in older people aged 65 years or above in Singapore.



This is a single-centre, randomised, observer-blind, active-comparator controlled, parallel-group, phase IV trial in 200 adults aged 65 years or older. Study participants will be assigned to one of two groups in a 1:1 ratio and followed for 1 year, with five scheduled visits. The control group will receive IIV3 at day 1, and an active comparator (Tetanus-diphtheria-pertussis vaccine) at day 180. Participants in the experimental group will receive IIV3 containing the same strains at day 1 and day 180. Endpoints are immunological, and include measures of HI titres, microneutralisation titres (MN) and cell-mediated immunity from first vaccination up to day 360.



If superiority of 6-monthly influenza vaccination is demonstrated, this study could form the basis for a larger clinical trial with influenza infection as the primary endpoint.



ClinicalTrials.gov, ID: NCT02655874 . Registered on 12 January 2016.
Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore. Barnaby_young@ttsh.com.sg.|Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore. Barnaby_young@ttsh.com.sg.
Barnaby
0000-0003-1010-2230
B
Young
Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore.|Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore.
Sapna
S
Sadarangani
Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore.
Haur Sen
HS
Yew
Infectious Diseases Service, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore, 229899, Singapore.
Chee Fu
CF
Yung
Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore.|Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore.|Saw Swee Hock School of Public Health, Thair Foundation Building, National University of Singapore, 12 Science Drive 2, Singapore, 117549, Singapore.
Yee Sin
YS
Leo
Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore.|Saw Swee Hock School of Public Health, Thair Foundation Building, National University of Singapore, 12 Science Drive 2, Singapore, 117549, Singapore.
Mark I-Cheng
MI
Chen
Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore.|Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore.
Annelies
A
Wilder-Smith
D000367:Age Factors; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood; D002985:Clinical Protocols; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects; D007115:Immunization Schedule; D000071497:Immunogenicity, Vaccine; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D007251:Influenza, Human / Q000175:diagnosis / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D008297:Male; D012107:Research Design; D012846:Singapore; D013997:Time Factors; D016896:Treatment Outcome; D014611:Vaccination
D000914:Antibodies, Viral; D007252:Influenza Vaccines
Antibody persistence; Haemagglutination inhibition; Influenza; Older people; Tropics; Vaccine