Virucidal activity of nasal sprays against severe acute respiratory syndrome coronavirus-2

Abstract

The highest viral loads of severe acute respiratory syndrome coronavirus-2 are detectable in the oral cavity, so a potential reduction of infectious virus by nasal and oral sprays could reduce transmission. Therefore, the inactivation capacity of nine nasal and oral sprays was evaluated according to EN 14476. One nasal spray based on sodium hypochlorite and one oral spray containing essential oils reduced viral titres by two to three orders of magnitude. Although clinical data are still sparse, nasal and oral sprays display a more convenient application for elderly people or those who are unable to rinse/gargle.

Keywords: Inactivation; Nasal spray; Nasopharynx; Oral cavity; Oral spray; Quantitative suspension test; Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2); Transmission.

Figure 1

Experimental set-up of the quantitative suspension test following virus titration to determine viral titres [50% tissue culture infective dose (TCID₅₀/mL)] (A). Virucidal activity of nasal sprays (B, Products A–G) and oral sprays (C, Products H and I) against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) (N=3; mean ± standard deviation). Virus was incubated with medium (control, grey bar) or various nasal and oral sprays (white bar) for 30 s. Hereafter, remaining viral titres (TCID₅₀/mL) were determined upon titration on VeroE6 cells according to Spearman–Karber. Cytotoxic effects are indicated as the lower limit of quantification (dotted line).