How long you should practice keeping your distance in social situations (or avoiding them altogether) depends on how long you are contagious (or how long the person from whom you’re distancing is contagious). For cold and flu, these periods are generally as follows:2 Cold: 1 to 2 days before symptoms until all symptoms clear up Flu: 1 day before symptoms until 7 days after feeling sick Social distancing can help keep colds from moving from colleague to colleague around the office and slow the spread of the flu during flu season.