Education Materials

Mount Sinai Hospital is a University of Toronto patient care, teaching, and research centre.
Mount Sinai Hospital is a University of Toronto patient care, teaching, and research centre.

Influenza Cohort Study 2010/11

The purpose of this study is to determine if healthcare workers are at increased risk for illness due to influenza relative to other working adults and to identify risk factors for influenza in healthcare workers. It will also describe the number of cases of influenza infection, how ill people become with their illness, and whether personal factors such as age or existing chronic conditions make a person more likely to become ill with influenza.

Who is being asked to participate?

We are asking for the participation of 1,650 healthcare workers and other working adults. Because participants need to make weekly reports to the study, it is important that all participants have access to a computer with the internet. Because swabs of the nose have to be obtained on the 1st or 2nd day of any acute respiratory illness (any "cold" or influenza), we are looking for people working at the hospitals listed below and for people who live or work close to Mount Sinai Hospital in downtown Toronto.

If I agree to participate, what do I need to do?

If you agree to participate in the study, you will be asked to:

  • Complete a web-based questionnaire about your job, and other possible risk factors for influenza infection (eg. Whether you have children, whether you take the subway to work). This takes about 15 minutes in total.
  • Complete a web-based questionnaire once a week from the beginning of November to the middle of April to report any symptoms of acute respiratory illness. You will receive an email reminder every Monday about this, with a link to the questionnaire, which takes 1-2 minutes to complete.
  • If you develop any symptoms that might be due to a viral infection (for instance, stuffy/runny nose, cough or fever), have a nasal swab done (these are easier than nasopharyngeal swabs), and complete an brief illness diary each day that you have symptoms. It takes about 2 minutes to complete each illness report.
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People who participate will also be asked if they would be willing to have a blood test at the beginning and end of the study (2 in total) to measure their immune system reaction to influenza. Also, if they would be willing to have extra nasal swabs taken, if they test positive for influenza, to help find out how long the virus survives in infected persons. Participants can choose whether or not to have the blood samples taken or do extra nasal swab testing if they get influenza.

How long will the study last?

The study will last until the end of the viral respiratory/influenza season this winter. This is usually mid-April, but can sometimes be a bit later.

Are there any risks to participating in the study?

There are no physical risks to participating in the study. Having a nasal swab is uncomfortable. If you choose to allow blood specimens to be taken, you may have some pain and bruising at the site.

Who can I contact if I am interested in the study?

You can call the main study office at 416-586-4800 ext.2767 or email us at A member of the study staff will then arrange to talk to you in detail about the study so you can decide whether or not you wish to participate.

You may also contact the investigator at your site:


The Influenza Cohort Study is a research study conducted by a team of researchers from across Canada. For more information about this study, please contact the Infectious Disease research office at

This website has been made possible through an unrestricted educational grant from Pfizer Canada Inc.
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