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Coronavirus variants are now linked to half of California cases



According to new data from the University of California, San Francisco, a variant of the coronavirus that was first discovered in Denmark is currently raging in California, accounting for more than half of the samples from 44 counties.

Scientists found that this variant, called L452R, is more infectious than the original strain of the virus, although it does not seem to spread faster than the British variant.

Equally disturbing is the new evidence that this variant is associated with an increased risk of serious illness and death. In addition, the vaccinated people seem to produce less protective antibodies to this variant, which suggests that it may evade our immune defenses.

This raises concerns that it may cause a pandemic, cause more deaths or reduce the effectiveness of vaccines.

Dr. Charles Qiu of the University of California, San Francisco concluded that the strain “should be designated as a variant of concern and requires urgent follow-up investigation.” His laboratory is working with the state Department of Public Health to find new ones. variant. The survey results were released on Monday morning.

Chiu̵

7;s laboratory estimates that this variant has appeared in California in May 2020, and its prevalence rose from 0% to more than 50% during the sampling period. People accused it of erupting in nursing homes, prisons, and emergency rooms at the Emperor’s Hospital in San Jose, where staff wearing inflatable Christmas trees may have infected at least 90 people.

“In many states, including Los Angeles and other places, the frequency of this phenomenon is increasing,” said Dr. Joe DeRisi, co-president of Chan Zuckerberg Biohub in San Francisco. The company performs about 45% of the genome sequenced in California, and 5 accounts for the country. Percentage of the total.

The new insights gained from tests conducted in the San Francisco mission area can provide a deeper understanding of the behavior of the virus. This variant is not limited to this community, but the test site at Mission BART Station on 24th Street, which is primarily a Latin community, attracted people from San Francisco and seven other Bay Area counties.

According to Dr. Diane Havlir, an infectious disease expert at UCSF, the variant accounted for 53% of the positive test samples collected from January 10 to January 27, a significant increase compared to November, when the mutant only accounted for positive 16% of the test.

With the help of the community in the mission area, the team was able to investigate key issues related to family transmission, symptoms, and childhood infections.

They found that the L452R variant strain has a higher “second attack rate”, that is, it spreads in the family when a family member is sick, indicating that it is more likely to spread than other strains.

Chiu’s laboratory also found evidence of increased transmittance. When the virus replicates in the human body and is released into the environment, it can detect faster reproduction speed and virus shedding. When the variant was introduced into cells and tissues grown in the laboratory, it showed greater infectivity.

To test whether antibodies can protect against this new virus, Chiu’s team tested the cultured virus in the laboratory against antibodies from people who had been vaccinated or had previously been infected with the virus, even though it was not the virus.

It was found that the ability of antibodies to resist mutant viruses was reduced by 2 to 4 times. This may reduce the protection of the vaccine or lead to widespread reinfection after the so-called “herd immunity”.

To understand whether this variant caused more serious disease, they studied the medical records of patients admitted to UCSF. After controlling for age, gender, and race, the research team found that people infected with this variant are significantly more likely to be admitted to the ICU and die.

The L452R variant was first discovered in Denmark in March last year and Los Angeles in May. Its spike protein has four mutations in the genetic code and is used by the virus to enter cells. This is why the virus is easier to spread, more easily to infect and spread.

Many other variants have appeared in other parts of the world. They are created when viruses make minor replication changes (called mutations).

The B.1.1.7 variant described for the first time in the United Kingdom contains 17 mutations, one of which increases infectivity and may cause more serious diseases. The variant was not found in the mission area test site in San Francisco. This does not mean it is not here, but at least at the time of research, this situation is not common.

The emergence of B.1.351 variants in South Africa and P.1 variants in Brazil is also worrying because they both have mutations that make pathogens more resistant to antibody attack.

Now, the new California variant does not seem as aggressive as the other three variants. It is less spread than the British version, and less resistant than the South African and Brazilian versions.


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