The oral cavity is a potentially high risk for Covid-19. Covid-19 infects cells below the voice box, in the airways and deep in the lungs, unlike flu viruses which start with your nose and throat. Other than via tiny particles inhaled in air, Covid-19 reaches those cells via fluid in the nose or throat that sneaks past your voice box (this is called aspiration) and slides down your windpipe, or trachea. Keeping your mouth and throat clear of infectious pathogens throughout the day and before you sleep at night (when most aspiration usually occurs) is paramount right now.
Brush and floss your teeth, swish and spit, and gargle twice with an antiseptic mouthwash. Since 2019-nCoV is vulnerable to oxidation, a mouth rinse containing oxidative agents such as 1% hydrogen peroxide or 0.2% povidone is recommended.
Tongue cleaning may play an important role, as it has been reported that ACE2 is the main host cell receptor of 2019-nCoV and plays a crucial role in entry of virus into the cell to cause final infection. As recent studies show there is a high expression of ACE2 receptors (highly enriched) in epithelial cells of the tongue.