Multiple Potential Targets of Methylene Blue against Enveloped Viruses: Lessons from Three Nobel Laureates

Abstract

At 120 years from the first Nobel Prize award, the world is struggling with a pandemic caused by a highly contagious coronavirus, the SARS-CoV-2. In the context of a paucity of specific and effective treatments for COVID-19 at more than one year from its emergence, attaining herd immunity by active immunization through vaccination does not represent a very close perspective at the present time. The resilience of enveloped viruses to many physical and chemical aggressions by shielding in a protective lipid bilayer have turned the epidemics with enveloped viruses capable of jumping between species into fearsome adversaries ever since the outbreaks of HIV, Marburg, Ebola, SARS-CoV, MERS-CoV or SARS-CoV-2. The works of three Nobel laureates of the 20th century Paul Ehlrich, Christian de Duve and Niels Ryberg Fynsen point out toward multiple potential uses of methylene blue (MB) in different formulations, against the functioning of enveloped viral pathogens. Here we describe these mechanisms and their potential uses in reducing COVID-19 pathogenesis, limiting the evolution toward a severe course of the disease and representing a preventive measure against SARS-CoV-2, complementary to vaccination programs.