Figure 1.

Plaque analysis and UV inactivation. (A) Infectious viral particles were detected by plaque assay under methylcellulose. Depicted is a single well of a six-well plate that had been inoculated with a limiting dilution of infectious viral stock. The inset is a higher magnification image of representative SARS-CoV-2 plaques. (B) A clarified solution containing infectious SARS-CoV-2 was subjected to UV exposure as detailed in Materials and Methods. Samples were taken from triplicate conditions at sequential exposures to UV-C irradiation. Each sample was then assessed for infectivity by the previously described plaque assay.