Effect of Influenza Vaccination of Children on Infection Rate in Hutterite Communities: Follow-Up Study of a Randomized Trial

Biao Wang; Margaret L Russell; Lorraine Moss; Kevin Fonseca; David J D Earn; Fred Aoki; Gregory Horsman; Paul Van Caeseele; Khami Chokani; Mark Vooght; Lorne Babiuk; Richard Webby; Stephen D Walter; Mark Loeb

doi:10.1371/journal.pone.0167281

Effect of Influenza Vaccination of Children on Infection Rate in Hutterite Communities: Follow-Up Study of a Randomized Trial

PLoS One. 2016 Dec 15;11(12):e0167281. doi: 10.1371/journal.pone.0167281. eCollection 2016.

Authors

Biao Wang¹, Margaret L Russell², Lorraine Moss¹, Kevin Fonseca³, David J D Earn^{4

5

6}, Fred Aoki⁷, Gregory Horsman⁸, Paul Van Caeseele⁹, Khami Chokani¹⁰, Mark Vooght¹¹, Lorne Babiuk¹², Richard Webby¹³, Stephen D Walter³, Mark Loeb^{1

4

5

14}

Affiliations

¹ Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.
² Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada.
³ Department of Microbiology and Infectious Diseases and Provincial Laboratory for Public Health, University of Calgary, Calgary, Alberta, Canada.
⁴ Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.
⁵ Michael G. De- Groote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada.
⁶ Department of Mathematics and Statistics, McMaster University, Hamilton, Ontario, Canada.
⁷ Departments of Medicine, Medical Microbiology and Pharmacology, and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada.
⁸ Saskatchewan Disease Control Laboratory, Regina, Saskatchewan, Canada.
⁹ Cadham Provincial Laboratory, Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada.
¹⁰ Saskatchewan Health, Prince Albert Parkland Health Region, Prince Albert, Saskatchewan, Canada.
¹¹ Saskatchewan Health, Five Hills Health Region, Moose Jaw, Saskatchewan, Canada.
¹² Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada.
¹³ St Jude Children's Research Hospital and WHO Collaborating Center, Memphis, Tennessee, United States of America.
¹⁴ Department of Medicine, McMaster University, Hamilton, Ontario, Canada.

Abstract

Background: An earlier cluster randomized controlled trial (RCT) of Hutterite colonies had shown that if more than 80% of children and adolescents were immunized with influenza vaccine there was a statistically significant reduction in laboratory-confirmed influenza among all unimmunized community members. We assessed the impact of this intervention for two additional influenza seasonal periods.

Methods: Follow-up data for two influenza seasonal periods of a cluster randomized trial involving 1053 Canadian children and adolescents aged 36 months to 15 years in Season 2 and 1014 in Season 3 who received the study vaccine, and 2805 community members in Season 2 and 2840 in Season 3 who did not receive the study vaccine. Follow-up for Season 2 began November 18, 2009 and ended April 25, 2010 while Season 3 extended from December 6, 2010 and ended May 27, 2011. Children were randomly assigned in a blinded manner according to community membership to receive either inactivated trivalent influenza vaccine or hepatitis A. The primary outcome was confirmed influenza A and B infection using RT-PCR assay. Due to the outbreak of 2009 H1N1 pandemic, data in Season 2 were excluded for analysis.

Results: For an analysis of the combined Season 1 and Season 3 data, among non-recipients (i.e., participants who did not receive study vaccines), 66 of the 2794 (2.4%) participants in the influenza vaccine colonies and 121 of the 2301 (5.3%) participants in the hepatitis A colonies had influenza confirmed by RT-PCR, for a protective effectiveness of 60% (95% CI, 6% to 83%; P = 0.04); among all study participants (i.e., including both those who received study vaccine and those who did not), 125 of the 3806 (3.3%) in the influenza vaccine colonies and 239 of the 3243 (7.4%) in the hepatitis A colonies had influenza confirmed by RT-PCR, for a protective effectiveness of 63% (95% CI, 5% to 85%; P = 0.04).

Conclusion: Immunizing children and adolescents with inactivated influenza vaccine can offer a protective effect among unimmunized community members for influenza A and B together when considered over multiple years of seasonal influenza.

Trial registration: Clinicaltrials.gov NCT00877396.

Publication types

Randomized Controlled Trial

MeSH terms

Adolescent
Canada
Child
Child, Preschool
Disease Outbreaks
Female
Follow-Up Studies
Humans
Incidence
Influenza Vaccines*
Influenza, Human / epidemiology*
Influenza, Human / prevention & control*
Male
Treatment Outcome

Substances

Influenza Vaccines

Associated data

ClinicalTrials.gov/NCT00877396

Grants and funding

This study was supported by the Canadian Institutes for Health Research and the National Institute for Allergy and Infectious Diseases. Sanofi Pasteur donated vaccines used for the study but provided no funding for the study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.