L452R COVID Variant in California Linked to Several Outbreaks a 'Red Flag'

A variant of the SARS-CoV-2 virus, which causes COVID-19, has been linked to several large outbreaks in California's Bay Area and is being seen more frequently in the state, health officials have said.

The variant—known as L452R—was first detected in Denmark in March last year and has since appeared in a number of U.S. states, including California.

The California Department of Public Health (CDPH) said in a statement on Sunday that the variant has been identified more frequently since November.

Dr. Charles Chiu, a virologist from the University of California San Francisco (UCSF), said in a press conference that the variant now accounts for around a quarter of all cases that he and his colleagues in the state were sequencing, despite representing less than five percent of cases only two months ago.

"It's concerning that we have a variant that was actually pretty uncommon prior to early December that since then, is now roughly 25 percent of all the cases that we're sequencing," Chiu said in the press conference, according to KTLA.

Chiu said the variant was "very rare" in California up until November even scientists had detected it in the state as early as May.

Scientists have linked the L452R variant to several large outbreaks in Santa Clara County—the most populous county in the San Francisco Bay Area.

"The fact that this variant was identified in several large outbreaks in our county is a red flag and must be investigated further," Santa Clara County health officer Sara Cody said in a statement.

"This virus continues to mutate and adapt, and we cannot let down our guard. This news underscores the need for everyone to follow all prevention measures and get vaccinated as soon as they are offered the vaccine."

Samples taken from COVID patients in Santa Clara county show that the variant was present in several large outbreaks, including those where very high numbers of people contracted the virus.

The L452R variant, which is different from the highly transmissible B.1.1.7 first detected in the U.K. that is now spreading in the United States, has also been detected in other locations around California, including Humboldt, Lake, Los Angeles, Mono, Monterey, Orange, Riverside, San Francisco, San Bernardino, San Diego and San Luis Obispo counties, according to the CDPH.

Public health are currently investigating this variant and its potential role in large outbreaks in the state. The true prevalence of the variant remains unclear because genomic sequencing—a technique which can reveal genetic changes in the virus—is not carried out evenly across the state or country.

"It is common to identify variants of viruses like SARS-CoV-2, and we are working with our federal, local and university partners to better understand this variant and how it might impact Californians," Erica Pan, State Epidemiologist for CDPH, said in a statement.

"It's too soon to know if this variant will spread more rapidly than others, but it certainly reinforces the need for all Californians to wear masks and reduce mixing with people outside their immediate households to help slow the spread of the virus. We also urge anyone who has been exposed to the virus to isolate from others to protect themselves and their loved ones."

More research is needed to determine whether or not the variant is more transmissible, but Chiu said there is a possibility it could be more infectious.

"We do not know whether it's more infectious yet," he said in the conference, according to SFGate. "However, given the fact that now it's roughly a quarter of the cases that we're seeing in California, maybe even more to the present, it is concerning that it may potentially be more infectious."

man receives COVID vaccine in California
A man has his temperature taken as he arrives at a Disneyland parking lot to receive a COVID-19 vaccine, January 13, 2021, in Anaheim, California. VALERIE MACON/AFP via Getty Images