On Sunday (January 17), public health officials announced that the SARS-CoV-2 variant L452R has become increasingly common in multiple Californian counties and is responsible for several large COVID-19 outbreaks in the state.
L452R was first detected in Denmark in March 2020 and later identified in the US last year, but recent sequencing results from California show that the proportion of COVID-19 cases associated with this variant rose from 3.8 percent to 25 percent between mid-November and late December, The Mercury News reports. One of these outbreaks, according to The Washington Post, was linked to a hospital staff member in San Jose wearing an inflatable Christmas tree costume who might have infected at least 90 people with the L452 variant.
“It is common to identify variants of viruses like SARS-CoV-2,” says Erica Pan, an epidemiologist at the California Department of Public Health, in a statement. “It’s too soon to know if this variant will spread more rapidly than others.”
A highly transmissible variant of SARS-CoV-2 known as B.1.1.7, first identified in the UK, is now spreading throughout the US and could become the dominant variant by March, according to the Centers for Disease Control and Prevention. There’s no evidence that B.1.1.7 causes more severe disease than other variants or that it will evade vaccines.
The L452 variant has three mutations that are different from B.1.1.7’s mutations, including one in the spike protein, which allows the virus to attach to and enter cells. The spike protein is the target of the two vaccines approved for use in the US. “Now that we know this variant is on the rise in our local communities, we are prioritizing it for study,” Charles Chiu, a virologist at the University of California, San Francisco (UCSF), says in the statement. “Researchers at UCSF and elsewhere will now be able to perform the critical laboratory experiments to determine whether or not this virus is more infectious or affects vaccine performance.”
“Because genomic sequencing is not done equally across the state or country, it is too soon to know how prevalent the 452 variant is statewide, nationally or globally,” the statement reads. Some experts say that the US is falling short in its sequencing efforts and a more coordinated approach is needed for effective surveillance of potentially more contagious new variants, The New York Times reported earlier this month. According to The Washington Post in late December, the US had genetically analyzed only about 0.3 percent of COVID-19 cases, putting the country 43rd in worldwide rankings of the percentage of cases sequenced at the time.