As we enter another influenza season, one question continues to vex medical and public health professionals: How do you stop people from catching the flu? The best way to prevent the flu is by getting an influenza vaccine every year. However, in the event of a large-scale influenza outbreak of a new virus strain or a pandemic, when influenza vaccine may not be promptly available, we will see tremendous demands on the health care system and its workers. Thus, it’s critical to understand how influenza is transmitted from person to person so that we can determine the best ways to protect health care workers while still enabling them to do their jobs.