Frequent occurrence of mutations in nsp3 and nsp4 of SARS-CoV-2, presumably caused by the inhaled asthma drug ciclesonide.

Mutations in nonstructural protein 3 (nsp3) and nsp4 of SARS-CoV-2, presumably induced by the asthma drug ciclesonide (which also has anti-SARS-CoV-2 activity), were counted 5,851 cases in the GISAID EpiCoV genome database. Sporadic occurrence of mutants not linked to each other in the phylogenetic tree were identified at least 88 times; of which, 58 had one or more descendants in the same branch. Five of these had spread to more than 100 cases, and one had expanded to 4,748 cases, suggesting the mutations are frequent, selected in individual patients, and transmitted to form clusters of cases. Clinical trials of ciclesonide as a treatment for COVID-19 are the presumed cause of the frequent occurrence of mutations between 2020 June and 2021 November. In addition, because ciclesonide is a common treatment for asthma, it can drive mutations in asthmatics suffering from COVID-19. Ciclesonide-resistant mutations, which have unpredictable effects in humans, are likely to continue to emerge because SARS-CoV-2 remains prevalent globally.