Figure 2 is a column graph showing the number of participants recruited each day from January to May 2013. There were a total of 3,702 participants recruited during this period. Notable recruitment activities included: on 22 April 2013 a “Welcome Back to Flutracking” email was emailed to all active participants with a suggestion that participants invite three people to join the survey, and 1,671 participants were recruited nationally from 22-24 April 2013; the first Flutracking survey was emailed to all active participants on 6 May 2013 and a Flutracking media release on “Man-flu” based on an analysis of severity of ILI symptoms by gender on 7 May, and 330 participants were recruited nationally on 6-7 May 2013.