Fig E4.

A 96-hour pretreatment with OM-85 inhibits Vero cell infection by SARS-CoV-2. Vero cells were pretreated with PBS or OM-85 (0.24-1.92 mg/mL) for 96 hours and then infected with SARS-CoV-2 (isolate USA-WA1/2020, 15 pfu/well) for 2 hours. Plaques were counted as described in Methods. Shown are average numbers ± SEM of pfu detected in 8 SARS-CoV-2–infected replicate wells pretreated with PBS or increasing OM-85 concentrations. Data were pooled from 2 independent experiments. A 2-tailed t test was used for statistical analysis after assessing the normality of sample distribution.