The variant identified in California is more infectious, more deadly, and cases double every 18 days

The variant of the coronavirus that was first found in California is more infectious than the original virus strain, is more likely to be associated with severe disease, and is partially resistant to antibodies, a preliminary study suggests.

“The devil is already here,” Charles Chiu, an infectious disease physician and sequencing expert at the University of California, San Francisco (UCSF), who led the study, told the LA Times. “I wish it were different. But science is science.”

Other experts say more data is needed before drawing conclusions about the variant.

The variant in California comprises two slightly different mutated forms of the virus, called B.1.427 and B.1.429. Also called CAL.20C, using another naming system. It was first found in California in July and has now been detected in the US and other countries, including Australia, Denmark, Mexico and Taiwan, according to GISAID.

The study authors said the new variant “should probably be designated as a variant of concern warranting urgent follow-up investigation,” Science reported Tuesday. A worrisome variant is a variant whose risk has been evaluated by experts for worrisome characteristics, such as being highly infectious, making people sicker, or escaping the immune response produced by vaccines.

The study has yet to be published online or formally peer-reviewed by experts.

Eric Topol, Founder and Director of the Scripps Translational Research Institute, said on Twitter that there was “a problem” with labeling the variant as “dangerous” without the study being published, and while COVID-19 cases, hospitalizations and deaths were declining despite the variant being widespread.

“If I were a reviewer, I would like to see more data from more infected people to corroborate this provocative claim,” David O’Connor, an expert in viral sequencing at the University of Wisconsin, Madison told Science.

Chiu and his colleagues examined 2,172 virus samples collected from 44 of California’s 58 counties between Sept. 1 and Jan. 29. In early September, they found no cases of B.1.427 / B.1.429. At the end of January, the variant accounted for almost a quarter of the sequenced cases. From the data, Chiu and his colleagues estimated that the number of cases caused by the variant was now doubling every 18 days, The New York Times reported.

Bruce Walker, immunologist and founding director of the Ragon Institute in Boston, told the LA Times that it was difficult to “untangle” all the different factors that contribute to the spread, including travel, vacation gatherings and restaurant dinners.

“I am more and more convinced that it transmits more than others at the local level,” William Hanage, an epidemiologist at Harvard’s TH Chan School of Public Health, told The New York Times. “But there is no evidence to suggest that it is in the same stage” as B.1.1.7, the variant first identified in the UK and now spreading across the United States.

The variant has a key mutation

The study authors identified some possibilities why the variant first detected in California, B.1.427 /B.1.429, could be more infectious than other variants in the state. First, they found that there was twice the amount of virus in the nasal swabs of those who were infected with B.1.427 /B.1.429, than those who were not. This could mean that people with the variant carry more virus particles and are more likely to pass the virus on to other people.

Second, the variant in California has a mutation, called L452R, in its spike protein, the part of the virus that is used to infect cells. The authors engineered a coronavirus with the L452R mutation and found that it could infect human lung tissue at least 40% more easily than other variants and was three times more infectious. L452R has not been seen in the existing concern variants.

Third, the scientists found that the antibodies produced by the body to fight the infection worked 50% less against B.1.427 /B.1.429 than the original variant of the coronavirus. The effect was less pronounced than for the variant first discovered in South Africa, which reduced the effectiveness of the antibodies to one sixth of their usual levels.

If the antibodies work worse, it could mean that there is a higher risk of reinfection and the vaccines could be less effective. However, another pre-press study found that the variant first found in California produced an antibody response similar to the original coronavirus.

Ciui and his team also said the variant could be more deadly.

The team studied 324 medical records from UCSF clinics and their medical center, and found that those with the variant were 4.8 times more likely to be admitted to intensive care and more than 11 times more likely to die, compared to those infected. with other variants, Science reported.

Ciui’s team said they adjusted for differences in age, gender and ethnicity when the number dropped. However, the numbers were small and it was not possible to say whether more people died due to the B.1.427 /B.1.429 variant itself, or whether overwhelmed hospitals and possible suboptimal care as a result contributed to their deaths, the authors said. .