Telephone survey to assess influenza-like illness, United States, 2006

Although current national response plans assume that most influenza-infected patients would stay home during a pandemic, surveillance systems might be overwhelmed and unable to monitor their health status. We explored the feasibility of using a nationwide telephone survey to monitor at-home patients. Of randomly selected adults surveyed during low influenza activity months (April-October 2006, surveillance weeks 17-41), 86% (7,268/8,449) agreed to answer questions about health status and influenza-like illness symptoms. Three percent (230/7,628) self-reported "flu." A subset (0.9%, 68/230) self-reported fever. In comparison, the Centers for Disease Control and Prevention's Sentinel Provider Network reported clinical influenza-like illness rates of 1.2%, 0.9%, and 1.2% for weeks 17, 20, and 41, respectively. The consistency between information obtained by telephone and surveillance data warrants further studies to determine whether telephone surveys can accurately monitor health status during seasonal influenza peaks and to augment current surveillance systems during a pandemic.