COVID-19: Topical agents and therapeutic prevention of nasal viral acquisition.

Since the spread of SARS-CoV-2 became a pandemic, the number of cases has been continuously growing worldwide. Numerous recommendations and suggestions have been published to prevent the acquisition and spread of the SARS-CoV-2, especially to protect health workers and front-line caregivers. SARS-CoV-2 is transmitted by aerosol, rendering air defense with suitable ventilation and adequate mask use pivotal. Recently, locally applied antiseptic, antiviral, or structure competitive receptor blockers were suggested to attack the virus at its main point of invasion, the nasal mucosa and nasopharynx. We discuss the most plausible and safe ideas to reduce viral load at the point of entry, and subsequently the spread of SARS-CoV-2 to the lower respiratory tract, lungs, and other organs. In addition, we analyze the value and recommend clinical trials employing topical trichloroacetic acid (TCA), a substance well known from dermatologic and cosmetic procedures. It has been proven to successfully block the nasal entry for airborne allergens, preventing the development of allergic rhinitis and asthma, and to be curative for early stages of viral infections entering through the oral mucosa. For SARS-CoV-2, TCA in a single, short-time application is expected to remodel the nasal and nasopharyngeal epithelia, eliminating both the receptors and cells responsible for viral entry and subsequent viral spread to the lower respiratory tract. Moreover, this may have therapeutic benefits for those recently infected by reducing local viral replication. Such procedures are cheap, safe, and can be conducted in almost every setting, especially in regions with inadequate financial and logistic resources.