Flutracking weekly online community survey of influenza-like illness: 2013 and 2014.

Flutracking is a national online community influenza-like illness (ILI) surveillance system that monitors weekly ILI activity and field vaccine effectiveness. This article reports on the 2013 and 2014 findings from Flutracking. From 2013 to 2014 there was a 14.0% increase in participants who completed at least 1 survey to 21,021 participants. By the end of the 2013 and 2014 seasons, respectively 59.7% and 59.1% of all participants had received the seasonal influenza vaccine. The 2013 Flutracking national ILI weekly incidence peaked in late August at 4.3% in the unvaccinated group, 1 week earlier than national counts of laboratory confirmed influenza. The 2014 Flutracking national ILI weekly incidence also peaked in late August at 4.7% in the unvaccinated group, in the same week as national counts of laboratory confirmed influenza. A lower percentage of Flutracking participants took two or more days off from work or normal duties in 2013 (peak level 1.6%) compared with 2014 (peak level 2.5%) and sought health advice in 2013 (peak level of 1.1%) compared with 2014 (peak of 1.6%). Flutracking ILI surveillance suggests that 2014 was a moderately more intense season than 2013 and similar to 2012.