The activity of hydroxychloroquine on viruses is probably the same as that of chloroquine since the mechanism of action of these two molecules is identical so there is a strong rationality for the use of chloroquine to treat SARS-CoV-2-related pneumonia (named COVID-19).
Chloroquine and hydroxychloroquine as available weapons to fight COVID-19
Repositioning of drugs for use as antiviral treatments is a critical need. It is commonly very badly perceived by virologists, as we experienced when reporting the effectiveness of azithromycin for Zika virus. A response has come from China to the respiratory disease caused by the new coronavirus (SARS-CoV-2) that emerged in December 2019 in this country. Indeed, following the very recent publication of results showing the in vitro activity of chloroquine against SARS-CoV-2, data have been reported on the efficacy of this drug in patients with SARS-CoV-2-related pneumonia (named COVID-19) at different levels of severity This has led in China to include chloroquine in the recommendations regarding the prevention and treatment of COVID-19 pneumonia.
There is a strong rationality for the use of chloroquine to treat infections with intracellular micro-organisms. Thus, malaria has been treated for several decades with this molecule. In addition, our team has used hydroxychloroquine for the first time for intracellular bacterial infections since 30 years to treat the intracellular bacterium Coxiella burnetii, the agent of Q fever, for which we have shown in vitro and then in patients that this compound is the only one efficient for killing these intracellular pathogens. Since then, we have also shown the activity of hydroxychloroquine on Tropheryma whipplei, the agent of Whipple’s disease, which is another intracellular bacterium for which hydroxychloroquine has become a reference drug. Altogether, one of us (DR) has treated ~4000 cases of C. burnetii or T. whipplei infections over 30 years (personal data).