Our results also suggest that self-swabs work generally well for quantitative measurement of viral loads. For influenza B, there was no significant difference between those obtained from selfswabs and the values predicted from the other 2 swabs by HCPs ( Figure 1G and 1H) . For influenza A, overall trends in viral loads between the 2 studies also appear similar ( Figure 1A and 1B) . Although self-swabs from the IRIS were associated with a lower viral load than the predicted value ( Figure 1E and 1F), these results should be interpreted with some caution as differences in the type of swabs and transport media used, collection site and technique, delays between collection and transport to the laboratory, and laboratory procedures between studies may have led to artifactual differences. We therefore only compared the predicted and observed viral loads within each study because results from the 2 studies were not directly comparable. Although the log-linear model fit the data well and provided reasonable predictions of viral loads in the HTS (Figure 1 ), more complex models might better represent the decline in viral loads over time. Although we did not explicitly model the shedding patterns of different influenza A subtypes, we have not previously identified substantial differences [2, 5] .