Hydroxychloroquine with or without Azithromycin in Covid-19

To the Editor: Cavalcanti et al. (Nov. 19 issue)(1) stated in the originally published Supplementary Appendix of their article (a corrected version is available at NEJM.org) that the use of "hydroxychloroquine and macrolides rapidly became part of the routine care of patients with Covid-19 [coronavirus disease 2019] in Brazil" during their trial, such that, as they stated in the originally published version of their article, "enrollment of patients with no previous use of these medications was challenging."(2) Preenrollment use of these medications was not an exclusion criterion until a change in their trial protocol (available at NEJM.org) was made 5 . . .