First variant Found in California In December, two new studies show that it is more contagious than previous forms of coronavirus, and such new mutants prevent a sharp decline in cases throughout the state and perhaps elsewhere. There is growing concern that it may be possible.
In one of the new studies, researchers discovered that the variant has spread rapidly in the San Francisco neighborhood over the past two months. Other reports have confirmed that this subspecies is proliferating throughout the state and have shown that it produces twice as many virus particles in the human body as other subspecies. The study also suggested that the mutant may be superior to others in evading the immune system and vaccines.
“I wish there was better news that this variant wasn’t important at all,” said Dr. Charles Chiu, a virologist at the University of California, San Francisco. “But unfortunately we only follow science.”
Neither study has yet been published in a scientific journal. Also, experts do not know how much public health threat this variant poses compared to other variants that are also prevalent in California.
A variant called B.1.1.7 arrived in the United States from the United Kingdom, where it rapidly became the predominant form of the virus, where hospitals were overloaded. A study of medical records in the United Kingdom suggests that B.1.1.7 is not only more contagious than previous variants, but also more deadly.
Some experts said the new variant of California was concerned, but unlikely to create the burden of B.1.1.7.
“I’m more and more convinced that this is more locally transmitted than others,” said William Hanage, an epidemiologist at Harvard’s School of Public Health who was not involved in the study. “But there is no evidence to suggest that it is in the same stadium as B.1.1.7.”
Dr. Chiu first happened to come across a new variant. In December, he and other California researchers were worried about the discovery of B.1.1.7 in the United Kingdom. They began examining samples from a positive coronavirus test in California and sequenced the viral genome to see if B.1.1.7 had arrived in their state.
On New Year’s Eve, Dr. Chiu was shocked to find a previously unknown variant that made up a quarter of the samples he and his colleagues collected. “I thought it was crazy,” he said.
It turns out that researchers at the Cedars Sinai Medical Center in Los Angeles discovered it separately The same variant surges High level in Southern California.Dr. Chiu is his First discovery, And Cedars-Sinai team Published 2 days later.
Since then, researchers have explored a new variant known as B.1.427 / B.1.429 in more detail to identify its origin and track its spread. So far, it has appeared in 45 states in several other countries, including Australia, Denmark, Mexico and Taiwan. But so far, it has only taken off in California.
It was initially unclear whether the variant was inherently more contagious than the other variants, or whether it surged in California due to a rally-widespread event.
“By chance, poor wedding and choir practice can make a big difference in frequency,” said Joe DeRisi, co-president of Chan Zuckerberg Biohub, who is investigating the spread of variants. ..
In a new study that will be posted online soon, Dr. Chiu and his colleagues analyzed 2,172 virus samples collected from across the state between September and January. At the beginning of September, researchers did not find any signs of B.1.427 / B.1.429. But by late January, it had become the predominant variant in California. Dr. Chiu and his colleagues estimate that the cases caused by the mutation are now doubling every 18 days.
After reviewing the medical records of 308 Covid-19 cases in San Francisco, Dr. Chiu and his colleagues found that a higher proportion of people died from the new variant than others. However, the result can be a statistical fluke. Since there were only 12 deaths in the group, the difference in deaths from one subgroup to another may not be maintained in larger samples.
Researchers also conducted experiments in the laboratory looking for evidence that the new variant had a biological advantage. In one study, they showed that they were at least 40 percent more effective at infecting human cells than previous mutants. When measuring genetic material found on cotton swabs used for coronavirus testing, researchers found that people infected with this variant produced twice as much viral load as other variants. ..
The study also found that new mutants can evade the immune system better than other mutants. Antibodies from people who recovered from infection from other variants were not very effective in blocking new variants in the laboratory.The same was true when researchers used serum From a vaccinated person.
Nevertheless, the effect of the mutant on immunity appears to be much smaller than that caused by a South African mutant called B.1.351. Dr. Chiu said it is not clear if the vaccine in use is less effective against B.1.427 / B.1.429.
“If we can vaccinate enough people, we can deal with these variants just because there is no persistent infection,” he said.
In another unpublished study, Dr. DeRisi and his colleagues scrutinized how variants change. Spread over the mission area, San Francisco’s predominantly Latin neighborhood.
Looking at the sample in late November, researchers found that 16 percent of the coronavirus belonged to B.1.427 / B.1.429. By January, after sequencing 630 genomes, they found that it accounted for 53 percent.
The researchers also studied the spread of this and other mutants in 326 households. They found that if someone in the house had B.1.427 / B.1.429, people were 35 percent more likely to get infected. If the person was infected with another variant, the proportion was only 26 percent.
“What we see is a modest but meaningful difference,” said Dr. DeRisi.
Dr. Chiu said the San Francisco study provided a microcosm of how the variants spread throughout the state. “The data they have from the mission district really supports our data, and vice versa,” he said.
However, Dr. Hanage of Harvard University is not convinced that this variant poses a major threat. Every time B.1.1.7 appeared in a new country, it exploded rapidly. In contrast, the variants found in California appear to be slowly becoming dominant.
Dr. Chiu and his colleagues were able to estimate when B.1.427 / B.1.429 occurred by comparing the mutations that occurred in the virus after it split from a common ancestor. .. The analysis showed late spring. If correct, that means the variant was lurking in California at a very low level, perhaps for more than four months.
“It’s not as big as the others,” said Dr. Hanage. He speculates that as scientists sequence more coronavirus genomes elsewhere, they will find more of these moderately rapidly spreading mutants. “Maybe variants are everywhere and I’m just looking at where the sequence is taking place,” he said.
You may soon gain some new insights into how seriously you take these new variants. B.1.1.7 arrived in California in early December and doubled every 12 days, but still accounts for only about 2 percent of the state’s coronavirus.
Now California will be a kind of virus cage match between the two variants. “My suspicion is that B.1.1.7 will win,” said Dr. Hanage.
However, Dr. Chiu believes that B.1.427 / B.1.429 may suppress newcomers and continue to dominate the state.
“We’ll see in the next few weeks,” he said.
Research examines a surge in variants in California, and the news is not good
Source link Research examines a surge in variants in California, and the news is not good