CDC, WHO Create Threat Levels for COVID Variants
Michael Diamond, MD, PhD, associate director, Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, Missouri
CDC, SARS-CoV2 Variants, updated March 16, 2021
WHO, Weekly Epidemiological Report, February 25, 2021
WHO, Weekly Epidemiological Report, March 16, 2021
Public Health England, Variants of Concern or Under Investigation, Updated March 15, 2021