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Does Seasonal Influenza Vaccination Affect the Incidence of pH1N1 Influenza?

This study has been completed.
Information provided by (Responsible Party):
Mount Sinai Hospital, Canada Identifier:
First received: October 23, 2009
Last updated: April 18, 2012
Last verified: April 2012

Since the onset of the 2009 pandemic, several observational public health investigations in Canada have identified evidence that suggests that adults, particularly younger adults, who have previously received seasonal influenza vaccine are at increased risk of infection with the 2009 pandemic strain of H1N1 (pH1N1). Investigations in Australia, the United States and the United Kingdom have not identified this effect. While it is not possible to have an answer to whether this affect is real prior to the second wave of the 2009 pandemic, it remains vital to future influenza vaccination programs that the hypothesis that, in 2009, seasonal vaccine increases or decreases the risk of pH1N1 infection be confirmed or refuted.

The objective of this study is to determine whether Ontario adults aged 18-60 years who receive the 2009 seasonal influenza vaccine will be at a 2 fold or greater increased risk of infection with influenza pH1N1 during the second or third wave of the 2009 pandemic.

Condition Intervention Phase
Biological: Fluviral influenza vaccine, 2009-2010
Biological: Normal saline
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Health Services Research
Official Title: A Randomized Controlled Trial of the Effect of Seasonal Influenza Vaccination on the Incidence of Infection Due to the 2009 H1N1 Influenza

Resource links provided by NLM:

Further study details as provided by Mount Sinai Hospital, Canada:

Primary Outcome Measures:
  • Number of pH1N1 Influenza Infections as Diagnosed by PCR From Mid-turbinate Swab [ Time Frame: day +7 post seasonal influenza vaccination (or placebo) to end of study ]
    Influenza infection (pH1N1) as diagnosed by PCR from self-collected mid-turbinate swab. Participant is asked to collect a swab when they have symptoms possibly compatible with an acute viral respiratory illness: 1) fever without another obvious source, 2) at least two new respiratory symptoms (runny or stuffy nose, sneezing, sore or scratchy throat, hoarseness, cough), or 3) one respiratory symptom (as above) and one systemic symptom (fever, malaise, muscle aches, headache, fatigue)

Enrollment: 468
Study Start Date: October 2009
Study Completion Date: July 2010
Primary Completion Date: March 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Seasonal influenza vaccination
Receipt of Fluviral seasonal (2009-2010, Canadian) influenza vaccination as per manufacturers specification
Biological: Fluviral influenza vaccine, 2009-2010
0.5 mL intramuscular
Placebo Comparator: Placebo
0.5 mL normal saline
Biological: Normal saline
0.5 mL intramuscular

Detailed Description:

This study will be an observer -blind randomized controlled trial.

This study will primarily recruit patients from an existing cohort of adult health care and other workers in Toronto, as of September 15, 2009, almost 1000 adults are participating in this cohort; with approximately 75 new cohort members being recruited weekly (target is 1300). Recruitment will be supplemented by enrollment at Hamilton Health Sciences Centre (N~3920 employees plus physicians & midwives) and Queen Elizabeth II Health Centre in Halifax (N~6000 employees plus physicians & midwives).

To date, health care workers in the Toronto cohort have been recruited at the Mount Sinai Hospital, Toronto East General Hospital, and North York General Hospital. Recruitment is just beginning at Sunnybrook Health Sciences Centre, and the University Health Network.

Non-health care workers are being recruited from several large Toronto employers of primarily office workers. These include the Ontario Agency for Health Protection and Promotion, the head offices of the Ontario Power Generation Corporation, the Art Gallery of Ontario, and the head offices of Scotia Bank. Non-health care workers should meet inclusion criteria and should not work primarily with children or from a home office.

Participants in the study are completing web-based diaries weekly, and, whenever they develop symptoms possibly compatible with influenza, are submitting nasal swabs, and completing symptom diaries daily while ill. Nasal swabs are tested by polymerase chain reaction (PCR) on a same or next day basis with antivirals prescribed to participants who develop influenza.


Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  1. 18 to 60 years old, inclusive, as of September 1st, 2009;
  2. understand the study, agree to its provisions, and give written informed consent prior to entry;
  3. available for follow-up during the study period;
  4. have convenient access to a computer with internet access and basic skills for use of the internet;

Exclusion Criteria:

  1. planning to spend more than two consecutive weeks outside of Canada from October 1, 2009 to April 15th 2010.
  2. received immunoglobulin within six months of study entry;
  3. has already received a 2009 seasonal influenza vaccine (southern or northern hemisphere)
  4. has had laboratory-confirmed infection with 2009 H1N1 influenza
  5. is participating in a clinical trial that would result in the receipt of investigational medication during the study period;
  6. allergic to eggs, to influenza vaccine, or any components of the seasonal influenza vaccine
  7. has had a previous severe adverse event associated with an influenza vaccine
  8. has a significant chronic underlying illness that would warrant seasonal influenza vaccine in a usual year, or is known to be pregnant.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01001325

Canada, Ontario
North York General Hospital
North York, Ontario, Canada, M2K 1E1
Mount Sinai Hospital
Toronto, Ontario, Canada, M5G 1X5
Sponsors and Collaborators
Mount Sinai Hospital, Canada
Principal Investigator: Allison J McGeer, MD Mount Sinai Hospital, New York
Principal Investigator: Brenda L. Coleman, PhD Mount Sinai Hospital, New York
Principal Investigator: Natasha Crowcroft, MD Ontario Agency for Health Protection & Promotion
Study Director: Karen Green, MSc Mount Sinai Hospital, New York
Study Director: Kevin Katz, MD North York General Hospital
Study Director: Mark Loeb, MD Hamilton Health Sciences Centre
Study Director: Donald Low, MD Mount Sinai Hospital, New York
Study Director: Shelly McNeil, MD Queen Elizabeth II Health Sciences Centre
Study Director: Matthew Muller, MD, PhD St. Michael's Hospital, Toronto
Study Director: Andrew Simor, MD Sunnybrook Health Sciences Centre
  More Information

Responsible Party: Mount Sinai Hospital, Canada Identifier: NCT01001325     History of Changes
Other Study ID Numbers: CRT113936
Study First Received: October 23, 2009
Results First Received: May 13, 2011
Last Updated: April 18, 2012

Keywords provided by Mount Sinai Hospital, Canada:
observer blind

Additional relevant MeSH terms:
Influenza, Human
Orthomyxoviridae Infections
RNA Virus Infections
Virus Diseases
Respiratory Tract Infections
Respiratory Tract Diseases
Immunologic Factors
Physiological Effects of Drugs processed this record on April 26, 2017