In-vitro virucidal activity of hypothiocyanite and hypothiocyanite/lactoferrin mix against SARS-CoV-2

Abstract

SARS-CoV-2 replicates efficiently in the upper airway during prodromal stage with resulting viral shedding into the environment from patients with active disease as well as from asymptomatic individuals. So far, virus spread has been exclusively contained by non-pharmacological interventions (social distancing, face masks, hand washing and several measures limiting business activities or movement of individuals)1,2. There is a need to find pharmacological interventions to mitigate the viral spread, supporting yet limiting the existing health protection measures while an effective and safe vaccine will hopefully become available. Hypothiocyanite and lactoferrin as part of the innate human immune system were shown to have a large spectrum of cidal activity against bacteria, fungi and viruses2,3. To test their virucidal activity against SARS-CoV-2 we conducted an in-vitro study. Here we show a dose-dependent virucidal activity of hypothiocyanite at micromolar concentrations, slightly improved by the presence of lactoferrin. The two substances are devoid of any cytotoxicity and may be administered combined by aerosol to exploit their antiviral activity at the port of entry (mouth, nasal cavity, conjunctiva) or exit (mouth, through emission of respiratory droplets) of SARS-CoV-2 in the human body. Furthermore, aerosol with hypothiocyanite and lactoferrin combined could also have a therapeutic effect in the lower respiratory tract, at the level of gas exchange units of the lung, preventing the devastating infection of alveolar type II cells where ACE2 is highly expressed. An in-vivo validation of in-vitro results is urgently required.