Figure 1.

Effect of nasal and oral sprays as well as carrageenans on SARS-CoV-2. A: SARS-CoV-2 was incubated for 30 min in 90% PBS or products A–F. The remaining infectious titer was determined by TCID₅₀ analysis on Vero E6 cells. Values shown are means ± SD derived from three independent experiments (n = 3), each performed in technical triplicates. Black lines indicate detection limits that increase upon cytotoxicity of the respective compound that was observed by light microscopy. B, C: TMPRSS2-expressing Vero E6 cells were treated with indicated concentrations of products A–F (B) or carrageenans (C) and infected with SARS-CoV-2. Infection rates were determined 2.5 days later by MTS assay (blue squares). For determination of toxicity, cells were treated with indicated concentrations of compounds in the absence of virus, and cellular ATP was measured by the CellTiter-Glo assay 2.5 days later (black triangles). Values shown in B and C are means ± SEM derived from two (products C, D, E, and F) or three (products A and B, ι- and κ-carrageenan, and ι-carrageenan) independent experiments (n = 2–3), each performed in technical triplicates. TCID₅₀, tissue culture infectious dose 50.