Are you infectious the whole time have flu?

It depends on the type of influenza virus and the individual's immune response. Generally speaking, people are most infectious in the 1-2 days before symptoms develop and for about 5-7 days after becoming symptomatic. However, some people may be contagious for a shorter or longer period. Children and individuals with weakened immune systems may be infectious for a longer period. People with the flu can spread the virus to others through respiratory droplets that are produced when they cough, sneeze, or talk. It is important to stay home and avoid contact with others if you have flu symptoms.