Lysozyme, discovered by Alexander Fleming six years before penicillin, is a key substance of natural immunity whose main effects “[…] are represented by antibacterial, antiviral and immunomodulatory actions. […] Regarding the antiviral activity, the molecule intervenes during the exocellular phase of the virus by activating defensive factors (activation of immune systems) and/or through an interaction with cell surface receptors (inhibition of syncytiogenic activity).”
Yet, to date, “[…] its importance in connection with natural immunity does not seem to be generally appreciated.”
In fact, while natural, innate and non-specific, immunity has been called into question to explain why subjects, i.e. children and young people, in whom it is particularly efficient, present SARS-CoV-2 infections with a generally very favorable and often asymptomatic course, no call into question has been made for lysozyme, although it is essential in natural immunity and is present in higher concentrations precisely in young subjects.
In June 2020, when the author, a Physician, proposed to counteract viroses through a preventive therapeutic approach aimed at improving the efficiency of the immune system (Todisco M., Contravirus, Vimarangiu, June 2020), Lysozyme naturally figured among the substances to be taken for this purpose, and in October 2020, with the resumption of the pandemic, the author started prescribing it to his SARS-CoV-2 positive patients.
Lysozyme and Covid-19 is a report of this experience, with the used doses and several testimonials. The author also reports the scientific arguments in favor of the use of this substance. Among them: a) a work that documented virus-induced fusion of cells normally found on the walls of the pulmonary alveoli, the pneumocytes, with pathological formation of “syncytium” at this level (Lysozyme is credited with inhibiting syncytiogenic activity); b) a study in which the authors have experimentally observed that Lysozyme inhibits viral replication of SARS-CoV-2; c) a recent work of Bioinformatics according to which, among other things, Lysozyme counteracts the infection of SARS-CoV-2 by covering that portion of the Spike protein [Receptor-Binding Domain (RBD)] that allows the virus to anchor itself to human cells.
 The quoted text is taken from the data sheet of the medicinal product Lisozima SPA, available on the website of the Italian Medicines Agency (AIFA). Original text: “[…]sono rappresentati dalle azioni antibatterica, antivirale ed immunomodulante. […] Nei riguardi dell’attività antivirale, la molecola interviene durante la fase esocellulare del virus attivando fattori difensivi (attivazione sistemi immunitari) e/o attraverso una interazione con recettori cellulari di superficie (inibizione attività sinciziogena).”
 The phrase in quotation marks is by Alexander Fleming. He pronounced it during the lecture on Lysozyme that he gave at the meeting of the Royal Society of Medicine in 1932.