Direct and Indirect Benefits of Influenza Vaccine Versus Placebo in Healthy Children
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|ClinicalTrials.gov Identifier: NCT00792051|
Recruitment Status : Completed
First Posted : November 17, 2008
Last Update Posted : December 30, 2014
|Condition or disease||Intervention/treatment|
|Influenza Virus Infection||Biological: Inactivated influenza vaccine Biological: Saline|
Design and subjects: A double-blind randomised controlled trial of 800 subjects aged 6-17 drawn from the general population and their 2000 household contacts. The subjects will be randomised in a 3:2 ratio to the intervention and placebo groups, respectively. Serum samples will be collected from subjects pre- and 1 month post-vaccination, and after the influenza season. Serum samples will be collected from household contacts at baseline and at the end of the influenza season. During the follow-up period, subjects and household members will keep symptom diaries and those reporting influenza-like-illness will be offered free doctor consultations or home visits where we will arrange for collection of nose and throat swabs.
Study instruments: An antibody titre of ≥40 in the post-vaccine serum will be used to define seroprotection to those particular strains, while a four-fold or higher increase in antibody titres between baseline and end-of-season follow-up of the household contacts will define influenza infection during the season. Subjects and household contacts will be asked to keep symptom diaries, and during episodes of ILI we will collect nose and throat swabs for laboratory confirmation of influenza infection; the primary serology results will then be compared with clinical and laboratory-confirmed influenza episodes.
Interventions: 1 (intervention) inactivated influenza vaccine (Vaxigrip, Sanofi Pasteur); 2 (placebo) saline injection.
Main outcome measures: The proportions of subjects and household contacts with serology-confirmed influenza infection during follow-up among the 2 intervention arms.
Analysis: Intention to treat, adjusting for within-household correlation in influenza attack rates.
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||2800 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||Triple (Participant, Care Provider, Outcomes Assessor)|
|Official Title:||A Randomised Controlled Trial of the Effectiveness of Vaccinating Children to Reduce Household Transmission of Influenza|
|Study Start Date :||September 2008|
|Primary Completion Date :||December 2010|
|Study Completion Date :||December 2010|
Active Comparator: 1
Biological: Inactivated influenza vaccine
0.5ml intramuscular single dose
Other Name: VAXIGRIP®, Sanofi Pasteur
|Placebo Comparator: 2||
0.5ml intramuscular, one dose
- The proportions of subjects and household contacts with serology-confirmed influenza infection during follow-up among the 2 intervention arms. [ Time Frame: nine months ]
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00792051
|The University of Hong Kong|
|Hong Kong, China|
|Principal Investigator:||Benjamin J Cowling, PhD||The University of Hong Kong|