Development of X4-fraction. Development of predicted fraction of X4-using viruses during treatment. Labels "R5" (R5-using) and "DM" (dual/mixed or X4-using) are Trofile results at the given times. The dotted line marks the 10% detection rate of standard Trofile assay. The black dots represent the time points when the NGS data was sampled, the solid lines are used for visualization of the fraction of X4-using viruses between these measured data points.