We used data from in vitro SARS-CoV-2/Vero-CCL81 cultures in the presence and absence of TDF (3-10 μM to infer the range of inhibition produced by the antiviral to an average single infected cell. Figure 2 shows computed ITDF for viral cycles of length 9.6-48h, which ranged between 0.54 to 0.99 (using the 2-ΔΔCt approximation) and between 0.50 and 0.98 (using the alternative simple approximation) for the lowest concentration of 3 μM. Experimental Ct and computed VR values using the 2-ΔΔCt approximation are shown in supplementary material Table S2. Given this range of estimates, for the next step we approximated the in vivo plausible range of SARS-CoV-2 replication inhibition per cycle due to TDF between 90% (namely high inhibition) and 60% (namely moderate inhibition) approximating the inhibition resulting from a plausible range of 12-36h for the viral cycle [21] .