Background: High attack rates of Influenzavirus among school-aged children tend to be expected to cause significant disruption of usual activities at school and at home.

Objective: To quantify the effect of influenza season on illness episodes, school absenteeism, medication use, parental absenteeism from work, and the occurrence of secondary illness in families among a cohort of children enrolled in an elementary school during the 2000-2001 influenza season.

Design: Prospective survey study.

Setting: Kindergarten through eighth grade elementary school in Seattle, Wash.

Patients or other participants: All children enrolled in the school were eligible for the study. Study participants were 313 children in 216 families.

Main outcome measures: The primary outcome measure was missed school days. Secondary outcomes measures included total illness episodes, febrile illness episodes, medication usage, physician visits, parental workdays missed, and secondary illnesses among family members of children in the study cohort. Differences between the rates of study events among participants when influenza was circulating and the event rates during the winter season when influenza was not circulating were used to calculate influenza-attributable excess events.

Results: Total illness episodes, febrile illness episodes, analgesic use, school absenteeism, parental industrial absenteeism, and secondary illness among family members were significantly higher during influenza season compared with the noninfluenza winter season. For every 100 children followed up for this influenza season, which included 37 school days, an excess 28 illness episodes and 63 missed school days occurred. Similarly, for every 100 children followed up, influenza accounted for an estimated 20 days of work missed by the parents and 22 secondary illness episodes among family members.

Conclusion: Influenza season has significant adverse effects on the quality of life of school-aged children and their families.