Question: how do you know if you are contagious with flu?
Answer: The contagious period for the flu begins about 1 day before symptoms start and can last as long as 5-7 days from when you first felt sick. You're generally contagious with a cold 1-2 days before your symptoms start, and you could be contagious as long as your symptoms are present—in rare cases, up to 2 weeks.