According to the Centers for Disease Control and Prevention (CDC), the best option to avoid the flu is to get the flu shot, and the best way to avoid other infectious diseases is to get the corresponding vaccination. For other contagious illnesses do the following:
Avoid close contact with others when you, or they, are sick;
Stay at home when you are sick;
Cover your mouth and nose with a tissue when you cough or sneeze;
Washing your hands often, with soap and water for at least 20 seconds;
Avoid touching your eyes, nose or mouth with unwashed hands (this is an important step to avoid catching the flu);
Clean and disinfect surfaces and objects at work.
For more information about stopping the spread of germs at work, refer to the CDC website.