Adults have an average of 2-3 colds per year. To take it up a notch, about 13% of the U.S. population will get the flu each year – that’s roughly 42 million people! It typically takes one to four days for symptoms to show up once you've caught the virus (so sneaky!). Adults can be contagious from the day before symptoms begin up to 10 days after the illness starts. Yikes! Here are some tips on how to stay healthy at the office (and what to do if you still get sick!).