A new strain of the coronavirus has been found in more than one-third of COVID-19 cases among Cedars-Sinai patients and may be contributing to the acceleration of the recent surge of cases across Southern California.
The strain, which investigators with Cedars-Sinai designated as CAL.20C, is believed to be in part responsible for the dramatic increase in cases over the last two months. The Cedars-Sinai findings did not indicate whether the strain is more deadly than current forms of the coronavirus.
CAL.20C is distinct from the virus version identified in Britain known as B.1.1.7, which is spreading in the U.S. and believed to be highly transmissible.
In Southern California, B.1.1.7 has been found in scattered coronavirus cases in Los Angeles, San Diego and San Bernardino counties. In contrast, the CAL.20C strain was identified in 36.4 percent of cases in the Cedars-Sinai study.
CAL.20C includes a virus variant the California Department of Public Health reported Sunday based on data submitted by Cedars-Sinai and other investigators.
This variant, dubbed L452R, is one of five recurring mutations that constitute the CAL.20C strain, which is propagating across the country, starting in Los Angeles County.
“The recent surge in COVID-19 positive cases in Southern California coincides with the emergence of CAL.20C,” said Dr. Eric Vail, assistant professor of pathology and director of molecular pathology in the Department of Pathology and Laboratory Medicine at Cedars-Sinai. Vail is co-corresponding author of the study.
The investigators, using publicly available databases, have detected the CAL.20C strain in multiple recent patient samples in Northern California, New York, Washington, D.C. and Oceania. In identifying the CAL.20C strain, Cedars-Sinai investigators examined SARS-CoV-2 virus samples from 192 patients at Cedars-Sinai who tested positive for coronavirus between Nov. 22 and Dec. 28, 2020.