It seems a lot of people took their doctor's advice and got flu shots. Carlos Quintanilla, with the Oregon Immunization Program, says if you didn't get a vaccination, it's not too late. The shot takes about two weeks to take effect.   Washing your hands several times a day is one way to avoid getting the flu. And he says, if you're sick, stay home. If you have a cough, cover your mouth with you arm or a tissue to avoid spreading the flu.