The burden of influenza-like illness in the US workforce

The disease burden of influenza-like illnesses (ILIs) on the working population has been documented in the literature, but statistical evidence of ILI-related work absenteeism in the USA is limited due to data availability.

To assess work absenteeism due to ILIs among privately insured employees in the USA in 2007-8 and 2008-9.

We used the 2007-9 MarketScan® research databases. Full-time employees aged 18-64 years, with the ability to incur work absence and continuously enrolled in the same insurance plan during each season were included. We identified ILI episodes using ICD-9 codes for influenza and pneumonia (480-487). For each season, we calculated the mean work-loss hours per ILI episode and the proportion of employees who had at least one ILI episode. Work-loss hours and ILI rates were examined by subgroups.

The mean number of work hours lost per ILI episode was 23.6 in 2007-8 and 23.9 in 2008-9. The proportion of employees with at least one ILI was 1.7% in 2007-8 and 1.2% in 2008-9. In both seasons, the proportion with ILI was higher among older (2.1 and 1.5%) and hourly workers (2.0 and 1.3%), workers in the southern region (1.9 and 1.3%) and those in oil, gas or mining industries (1.9 and 1.4%).

Our results indicate that the disease burden associated with ILIs in the working population is not trivial and deserves attention from policymakers and health care professionals to design effective strategies to reduce this burden.