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

NCT ID: NCT00792051

Last Updated: 2014-12-30

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

2800 participants

Study Classification

INTERVENTIONAL

Study Start Date

2008-09-30

Study Completion Date

2010-12-31

Brief Summary

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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.

Detailed Description

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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.

Conditions

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Influenza Virus Infection

Keywords

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influenza vaccination children Influenza-like illness

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

PREVENTION

Blinding Strategy

TRIPLE

Participants Caregivers Outcome Assessors

Study Groups

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1

Influenza vaccine

Group Type ACTIVE_COMPARATOR

Inactivated influenza vaccine

Intervention Type BIOLOGICAL

0.5ml intramuscular single dose

2

Group Type PLACEBO_COMPARATOR

Saline

Intervention Type BIOLOGICAL

0.5ml intramuscular, one dose

Interventions

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Inactivated influenza vaccine

0.5ml intramuscular single dose

Intervention Type BIOLOGICAL

Saline

0.5ml intramuscular, one dose

Intervention Type BIOLOGICAL

Other Intervention Names

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VAXIGRIP®, Sanofi Pasteur

Eligibility Criteria

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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.
Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Research Fund for the Control of Infectious Diseases

UNKNOWN

Sponsor Role collaborator

Research Grants Council, Hong Kong

OTHER

Sponsor Role collaborator

Centre for Health Protection, Hong Kong

OTHER_GOV

Sponsor Role collaborator

The University of Hong Kong

OTHER

Sponsor Role lead

Responsible Party

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The University of Hong Kong

Principal Investigators

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Benjamin J Cowling, PhD

Role: PRINCIPAL_INVESTIGATOR

The University of Hong Kong

Locations

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The University of Hong Kong

Hong Kong, , China

Site Status

Countries

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China

References

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Cowling BJ, Perera RA, Fang VJ, Chan KH, Wai W, So HC, Chu DK, Wong JY, Shiu EY, Ng S, Ip DK, Peiris JS, Leung GM. Incidence of influenza virus infections in children in Hong Kong in a 3-year randomized placebo-controlled vaccine study, 2009-2012. Clin Infect Dis. 2014 Aug 15;59(4):517-24. doi: 10.1093/cid/ciu356. Epub 2014 May 13.

Reference Type DERIVED
PMID: 24825868 (View on PubMed)

Cowling BJ, Ng S, Ma ES, Fang VJ, So HC, Wai W, Cheng CK, Wong JY, Chan KH, Ip DK, Chiu SS, Peiris JS, Leung GM. Protective efficacy against pandemic influenza of seasonal influenza vaccination in children in Hong Kong: a randomized controlled trial. Clin Infect Dis. 2012 Sep;55(5):695-702. doi: 10.1093/cid/cis518. Epub 2012 Jun 5.

Reference Type RESULT
PMID: 22670050 (View on PubMed)

Cowling BJ, Ng S, Ma ES, Cheng CK, Wai W, Fang VJ, Chan KH, Ip DK, Chiu SS, Peiris JS, Leung GM. Protective efficacy of seasonal influenza vaccination against seasonal and pandemic influenza virus infection during 2009 in Hong Kong. Clin Infect Dis. 2010 Dec 15;51(12):1370-9. doi: 10.1086/657311. Epub 2010 Nov 10.

Reference Type RESULT
PMID: 21067351 (View on PubMed)

Other Identifiers

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GML003.4

Identifier Type: -

Identifier Source: org_study_id