Grant: Operating Grant

Influenza (the flu) makes a lot of people sick each year. Young children, the elderly, and those with chronic illnesses are among the high-risk groups that are more likely to be hospitalized or die from influenza. There is also growing evidence that influenza may trigger heart attacks and strokes. However, past studies were not able to identify influenza as the specific cause of these events. Therefore, the first objective of this proposed research is to see if influenza infections that are confirmed by lab tests are related to heart attacks and strokes. We will do this by linking data from the Public Health Ontario Laboratories and several large hospitals in Ontario to health care records. We will then use statistical tests to see if people are more likely to have a heart attack or stroke shortly after having influenza (confirmed by lab testing), compared to other times. Getting a flu shot each year is the most effective way to prevent influenza infection, but we are not sure how well influenza vaccines actually work, especially for high-risk groups. The second objective of this proposed research is to use the linked data to study how well influenza vaccines work to protect these groups of people from being hospitalized or dying from influenza. We will do this by looking at people who tested positive influenza and those that who tested negative for influenza and see how many in each group received the vaccine. These two related studies will greatly increase our understanding of how harmful influenza infections can be and how well influenza vaccines work.