This is a research article published as information for health care professionals and public officials, and for an open peer review. It is not medical advice. Summary I reviewed the scientific literature on hydroxychloroquine (HCQ), azithromycin (AZ), and their use for COVID-19. My conclusions: HCQ-based treatments are effective in treating COVID-19, unless started too late. Studies, cited in opposition, have been misinterpreted, invalid, or worse. HCQ and AZ are some of the most tested and safest prescription drugs. Severe COVID-19 frequently causes cardiac effects, including heart arrhythmia. QTc prolonging drugs might amplify this tendency. Millions of people regularly take drugs...