Retrospective Study to Identify Whether Doxycycline in SARS-CoV-2 Infection Protects Against Progression to a Severe Form.

A new coronavirus, the third documented animal-to-human passage, emerged in Wuhan , China in the last quarter of 2019. Acne patients on doxycycline escaped seasonal viruses, showing the interest of this antibiotic as a possible treatment against COVID-19.

The antiviral action of tetracyclines can be explained by different mechanisms. First of all, tetracyclines are modulators of innate immunity by decreasing NF-B expression, inhibiting inflammatory cytokines such as TNF-α, IL-1β and IL-6, inflammatory granulomas and free radical release . This action is obtained at doses lower than those necessary to obtain an antibiotic effect. Another possible action of tetracyclines is their ability to chelate zinc from matrix metalloproteinases (MMPS). The coronavirus family is known to bind to host MMPs, particularly for viral survival. Their chelating activity may help inhibit SARS-CoV-2 infection by limiting its ability to replicate in the host. Finally, tetracyclines could have a direct action by inhibiting the replication of single-stranded RNA virus, such as the SARS-CoV-2 coronavirus.We therefore propose a larger comparative study using data from the French National Health Data System.