Fig. 3.

Change in Ct value is associated with time since the first positive test. In individuals with longitudinal samples, the change in Ct value and time since the first positive test was plotted. Data points were only included where a minimum of three tests (including the first positive result) from different individuals (only including nasopharyngeal and nose and throat swabs) were performed. The blue line represents the linear regression line and the red dotted lines represent the 95% confidence intervals.