California Joins Colorado With Highly Transmissible Covid Strain
An empty hallway inside Collins Elementary School in Pinole, California, U.S. (Photographer: David Paul Morris/Bloomberg)

California Joins Colorado With Highly Transmissible Covid Strain

A second U.S. case of the highly transmissible Covid-19 variant that emerged in the U.K. has been detected in California, a day after Colorado reported the nation’s first known infection.

California Governor Gavin Newsom revealed the case Wednesday during a virtual conversation with Anthony Fauci, the nation’s top infectious disease expert. Meanwhile, Colorado officials said on Wednesday that they’re investigating another possible infection involving the new strain in their state.

State health officials in Colorado said Wednesday a second potential case was being investigated there, and that tests were being conducted on samples from other people who may have been exposed to the mutation

“I’m not surprised that you have a case,” Fauci, the director of the National Institute of Allergy and Infectious Diseases, told Newsom during their conversation. “We likely will be seeing reports from other states too.”

California Joins Colorado With Highly Transmissible Covid Strain

In Colorado, both patients were members of a National Guard unit sent on Dec. 23 to Good Samaritan Society Nursing Home in Simla, Colorado, as the facility struggled with staff shortages caused by a coronavirus outbreak. Routine testing conducted the day after they arrived showed telltale signs of the recently emerged variant that has been spreading widely in the U.K.

The first case, found in a man in his 20s, was confirmed Tuesday. The second Colorado is “highly suspicious” but still under evaluation, with results likely within a week, according to state scientific director Emily Travanty.

Genetic sequencing of 22 additional samples by Colorado health officials hasn’t turned up any other signs of the variant, known as B.1.1.7. Another 12 are awaiting more detailed tests.

“There is a lot we don’t know about this variant,” Colorado Governor Jared Polis said. “But if it does transmit more quickly, more people will get it and more people will be hospitalized.”

The U.S. Centers for Disease Control and Prevention is looking into whether the mutations will make existing treatments -- including convalescent plasma and monoclonal antibodies -- less effective, Henry Walke, the agency’s Covid-19 incident manager, said on a call with reporters Wednesday.

There is no reason measures like wearing a mask and social distancing would be less effective in preventing transmission of the new strain, Walke said.

Colorado recorded 451 new cases of Covid-19 Wednesday, while California reported 30,921 new daily cases, less than the 14-day average of about 39,000. The country’s most populous state has had 432 Covid-19 deaths on Tuesday, California’s Newsom said, marking a daily record.

Health officials believe the vaccine will remain effective against the new strain. So far, 84,000 doses have been administered in the state and Colorado is now allowing all residents over the age of 70 to be vaccinated, subject to availability.

All 26 residents of the Colorado nursing home in Simla where the first mutant strain was recorded tested positive for Covid-19, as did 20 of the facility’s 34 regular staff members, said Rachel Herlihy, Colorado’s lead epidemiologist.

The National Guard didn’t arrive until long after most of the cases associated with the outbreak had surfaced, with preliminary results yielding little evidence the variant virus was circulating in the facility, she said.

Public-health officials are investigating close contacts for both patients to determine whether they became infected through other work or outside activities, Herlihy said. Neither traveled internationally and both are isolating. All of their close contacts will also be asked to quarantine for the next two weeks to try to avert further spread of the virus, she said.

Missing Gene

The state is committed to doing full genetic sequencing on any samples that show signs of the U.K. variant, Travanty said. Samples are flagged when only two of the three genes targeted by the gold-standard PCR tests used by the state are found, indicating a mutation has occurred in the third -- the critical Spike protein that helps give the virus its name.

The missing gene is known as the “S dropout,” Travanty said. It is present but rendered undetectable by the test because of the mutation, making it a signature of the variant, she said. When laboratories find that red flag, it indicates more investigation is needed.

“We are sequencing all samples with the S dropout to see how widespread this is in the state,” she said. “We are also increasing our surveillance across the state with CDC sequencing, in addition to the sequencing that we’re doing here at the state lab.”

The CDC launched a national surveillance system to detect novel strains of SARS-CoV-2 in November, and is scaling up now so that it can sequence 750 samples each week, said Greg Armstrong, director of the CDC’s advanced molecular detection program, and the leader of the team monitoring the coronavirus variants at the agency.

©2020 Bloomberg L.P.

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