Direct and Indirect Benefits of Influenza Vaccine Versus Placebo in Healthy Children

December 29, 2014 updated by: The University of Hong Kong

A Randomised Controlled Trial of the Effectiveness of Vaccinating Children to Reduce Household Transmission of Influenza

While immunisation of school-age children against influenza is not recommended in Hong Kong, past experience in Japan and elsewhere suggests that immunisation of children may protect the wider community through its indirect transmission-limiting impact as well as the direct immunologic protection afforded vaccinated children themselves. We aim to assess whether vaccinating children against influenza protects vaccinees as well as their household contacts from infection.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

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

Enrollment (Anticipated)

2800

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
      • Hong Kong, China
        • The University of Hong Kong

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • All vaccinees must be Hong Kong residents aged between 6 and 17.

Exclusion Criteria:

  • Vaccinees should not be allergic or hypersensitive to the active substances or components (eggs, chicken proteins, formaldehyde, neomycin, etc.) used in the vaccines or where vaccination is otherwise contraindicated. Subjects should not have an underlying immunocompromised condition or be receiving immunosuppressive agents.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: 2
Biological: Saline
0.5ml intramuscular, one dose
Active Comparator: 1
Influenza vaccine
Biological: Inactivated influenza vaccine
0.5ml intramuscular single dose
Other Names:
  • VAXIGRIP®, Sanofi Pasteur

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
The proportions of subjects and household contacts with serology-confirmed influenza infection during follow-up among the 2 intervention arms.
Time Frame: nine months
nine months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

The University of Hong Kong

Collaborators

Research Grants Council, Hong Kong
Research Fund for the Control of Infectious Diseases
Centre for Health Protection, Hong Kong

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2008

Primary Completion (Actual)

December 1, 2010

Study Completion (Actual)

December 1, 2010

Study Registration Dates

First Submitted

November 13, 2008

First Submitted That Met QC Criteria

November 13, 2008

First Posted (Estimate)

November 17, 2008

Study Record Updates

Last Update Posted (Estimate)

December 30, 2014

Last Update Submitted That Met QC Criteria

December 29, 2014

Last Verified

December 1, 2014

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • GML003.4

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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