A new SARS-CoV-2 variant, CAL.20C, has been detected in southern California amid a surge in local infections and is spreading through and beyond the United States, according to a research letter published yesterday in JAMA.Researchers at Cedars-Sinai Medical Center (CSMC) in Los Angeles analyzed COVID-19 strains before and after the surge in cases in southern California in October 2020.
Before October, most coronavirus strains there originated from the 20C clade (group of viruses evolved from the same ancestor), which emerged in New York via Europe in the early stages of the pandemic.CAL.20C, or 20C/S:452R;/B1429, was first seen in 1 of 1,247 COVID-19 samples in Los Angeles County in July, but was not observed again in the region until