Figure 1

The ultraviolet C (UVC) light irradiation system. A UVC wavelength of 253.7 nm, 500 μW/cm2 is used. The length and diameter of the light tube are 295 ± 3 mm and 15.5 ± 0.5 mm, respectively. SARS-CoV-2 (5 mL) with a titer of 5 × 104 50% tissue culture infective dose (TCID50/mL) or (1 mL) with a titer of 1.78 × 106 TCID50/mL are placed in a 10 cm2 dish, 30 cm below the UVC light tube, and are continuously and individually irradiated using a UVC lamp for 0, 5, 15 or 30 s.