It has been a year since Wuhan health authorities first issued a bulletin about a cluster of pneumonia cases of unknown cause, first bringing what would become the COVID-19 pandemic to the attention of the World Health Organization. Now, a mutation that significantly increases SARS-CoV-2’s transmissibility has been detected in the U.S. On Dec. 29, Colorado public health authorities reported the first known case of infection with the SARS-CoV-2 VUI 202012/01 (Variant Under Investigation, year 2020, month 12, variant 01), also called B.1.1.7, variant in the U.S. The patient in question, a male in his 20s, has not traveled internationally, indicating that the variant is already circulating more widely in the U.S.