Response to: 'Hydroxychloroquine ineffective for COVID-19 prophylaxis in lupus and rheumatoid arthritis' by Singer et al .

Competing Interests: Competing interests: PK reports personal fees from GlaxoSmithKline, Sanofi-Aventis, Pfizer, Abbvie, Novartis Pharma, Eli Lilly and Bristol-Myers Squibb. FB reports personal fees from Boehringer, Bone Therapeutics, Expanscience, Galapagos, Gilead, GSK, Merck Sereno, MSD, Nordic, Novartis, Pfizer, Regulaxis, Roche, Sandoz, Sanofi, Servier, UCB, Peptinov, TRB Chemedica and 4P Pharma. AHK reports grants from National Institutes of Health (NIH)/National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) and Rheumatology Research Foundation and personal fees from Exagen Diagnostics, Inc. and GlaxoSmithKline. Drs Liew and Graef have disclosed no conflicts of interest or competing interests. JAS reports grants from NIH/NIAMS/National Institute of Allergy and Infectious Diseases/Autoimmune Centers of Excellence, the Rheumatology Research Foundation, the Brigham Research Institute, and the R. Bruce and Joan M. Mickey Research Scholar Fund as well as personal fees from Bristol-Myers Squibb, Gilead, Inova, Janssen and Optum.