Our analyses represent the first comparison of Google Flu Trends data with data on laboratory-confirmed influenza virus infections. Prior studies have demonstrated that Google Flu Trends can estimate rates of nonspecific ILI in New Zealand, Europe, and the United States [2, 20, 21] . We have demonstrated that Google Flu Trends performs less well when estimating surveillance data for laboratory-confirmed influenza, which is not surprising, as the Google Flu Trends algorithm was developed using only ILI data.