A coronavirus strain first detected in Los Angeles, Calif. appears to be spreading across the U.S., though scientists are still studying the variant’s degree of transmissibility and virulence.
A team of researchers from Cedars-Sinai say the variant, called CAL.20C, was first discovered in July before it began rapidly circulating in November and December. Findings were published in a JAMA Network research letter on Thursday, drawing on 185 analyzed samples from a total of 2,311. The team identified the variant in 36% of the 185 samples.
“Since then, this variant’s prevalence has increased in California state and Southern California, where on January 22, 2021, it accounted for 35% (86 of 247) and 44% (37 of 85) of all samples collected in January, respectively,” a research letter reads.
This variant has also been found in 26 states, Washington D.C., and six countries, study authors say.
“The strain now accounts for nearly half of current COVID-19 cases in Southern California — nearly double the percentage in the region compared to just a month ago, according to the Cedars-Sinai research,” reads a related release from Cedars-Sinai.
Last month, the researchers said CAL.20C had been identified in more than one-third of LA COVID-19 patients.
“CAL.20C is moving, and we think it is Californians who are moving it,” said Jasmine Plummer, a research scientist at the Cedars-Sinai Center for Bioinformatics and Functional Genomics, associate director of the Applied Genomics, Computation & Translational Core at Cedars-Sinai and study co-author.
The release notes that the Los Angeles International Airport (LAX) saw some 2 million passengers monthly in November and December, serving as a “key U.S. gateway for a number of the foreign destinations, including Australia, and New Zealand, where CAL.20C now is found.”
Dr. Eric Vail, assistant professor of pathology and director of molecular pathology in the Department of Pathology and Laboratory Medicine at Cedars-Sinai and co-senior study author, said the team is interested in the strain because it involves mutations along the spike protein, which the virus uses to infect healthy cells.
The Cedars-Sinai team said the findings were limited due to a small set of local samples, but that the discovery is still important for virus surveillance.
“Because this study was limited to databases of publicly available genomes and a comparatively small set of local samples, the possibility of collection bias cannot be ruled out. Additionally, as clinical outcomes have yet to be established, the functional effect of this strain regarding infectivity and disease severity remains uncertain. Nevertheless, the identification of this novel strain is important to frontline and global surveillance of this evolving virus.”