Trends in influenza A viral load are shown in Figure 1A for 138 subjects from the IRIS and in Figure 1B for 188 subjects from the HTS. In the IRIS, the influenza A viral loads determined from swabs taken at the second measurement were slightly lower on average than the expected values based on the random-effects regression model ( Figure 1E ). The mean difference between observed and predicted viral load on the second measurement was 20.50 (95% CI, 2.69 to 2.31) log 10 vp/mL. In the HTS, viral loads determined from swabs taken at the second measurement were slightly higher on average than the expected values based on the random-effects regression model ( Figure 1F) , with a mean difference of 0.31 (95% CI, .08-.54) log 10 copies/mL. Trends in influenza B viral loads are shown in Figure 1C for 58 subjects from the IRIS and in Figure 1D for 118 subjects from the HTS. In both studies, the differences between observed and predicted viral loads on the second measurement were small and statistically insignificant ( Figure 1G and 1H) . In the IRIS, the mean difference was 0.16 (95% CI, 2.18-.51) log 10 vp/mL, and in the HTS, it was 0.14 (95% CI, 2.16-.43) log 10 copies/mL.