Omicron: a small virus that had no chance of finding a home in the outside world and then left to find a new host
That was a conundrum. How can something have ripped through over 120 countries in two months and not be detected for so long? It was a puzzle if Omicron was hidden all that time but it was parallel to the earlier ones.
It took shelter in a small group of people who didn’t have any involvement with the outside world and didn’t know how to use a computer. It had a home in someone that it couldn’t overcome, leaving it with the viruses territory in which to replicate and change. It fell back into the animal world, not the bats in which it first found a host, but into some new species that would give rise to novel ways of doing things.
The risk of reverse zoonosis was known to exist. In April 2020, just a few months after the virus began spreading internationally, it migrated into mink farms in the Netherlands, triggering the deaths or preventive slaughter of millions of the animals—and a few months later it traveled back into humans.
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In the study, published last week in the Proceedings of the National Academy of Sciences, researchers took a structural biology approach—studying the shapes of molecules within the virus—to examine mutations in Omicron’s spike protein, which allows it to invade cells. The mice’s cells had a version of the receptors present in humans that were more efficient in bind to the viruses compared to the cells with the other version. The binding between pseudoviruses and cells engineered to include a mouse or human receptor was confirmed by assembling them. They found that Omicron had more affinity for the mouse version.
As the world enters a new year, many public health and infectious disease experts predict that monitoring for new coronavirus variants will be an increasingly important part of Covid-19 mitigation efforts – and some are turning their attention to a surge in cases in China.
“We haven’t seen any major jumps in terms of Omicron evolution in some time,” he said. We have to keep an eye on it at that stage because it is getting to that point.
There are at least 29 countries in which XBB. 1.5 can be found, and it is the most transmissible form of Omicron to date.
Dr. William Schaffner is a professor and medical director at the National foundation for infectious diseases and he said that it is a worry. “And that, of course, has led to the CDC’s very recent announcement that they are going to oblige people who come to this country from China to be tested and test negative before they can come into the country.”
Travelers from China will need to show a negative test result if they want to travel to the US. Passengers traveling to the US from China will need to get tested no more than two days before flying and present proof of the negative test to their airline before boarding.
The CDC is going to expand its Genomic Profiling program to airports in Los Angeles and Seattle with about 500 weekly flights from at least 30 countries.
The US testing requirements for travelers will “buy some time,” but they won’t prevent new Covid-19 cases from coming to the United States or new variants from emerging, said Dr. Carlos Del Rio, the executive associate dean for the Emory School of Medicine and Grady Health System in Atlanta.
“I don’t think we’re going to see much benefit from the travel requirements.” “The most important thing we need right now is, we need the Chinese to have more transparency and tell us exactly what’s going on, and that is pretty much a diplomatic decision. This is about diplomacy.”
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It is essential that you have lots of cases because the more cases you have, the more likely it is that the virus will accumulate genes that will allow it to evade detection.
“So when you have a situation like what’s starting to turn out in China, where you’re going to have millions upon millions of infections, every one of those infections is just one additional opportunity for the virus to pick up a random mutation that might make it better at infecting people,” he said. “Combine that with the fact that the Chinese population has been using less-than-optimal vaccines and has apparently not been as good about putting boosters into their population as other countries have, that means that there’s probably a lower amount of immunity in the population.”
The GISAID Data Science Initiative announced that it has released genome sequence data from 167 SARS-CoV-2 samples collected during the current outbreak in China. SARS-CoV-2 is the name of the virus that causes Covid-19. GISAID also confirmed that the sequences from China “all closely resemble known globally circulating variants seen in different parts of the world between July and December 2022,” compared with the 14.4 million genomes in GISAID’s database.
Covid-19 is in a relatively “stable” state right now in the United States, but the nation still sees about 350 deaths related to the disease each day, said Dr. Jessica Justman, an associate professor of medicine in epidemiology at Columbia University Mailman School of Public Health and senior technical director of the global health program ICAP.
New hospital admissions in parts of the US have increased nearly 50% over the past month, and there is concern that this will be the case after the winter holidays.
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Justman said that they are going to look at new types of concern in the future. “The question is: Will we go back to a point where we have a variant of concern that causes such severe illness that we don’t get the benefit of our protection from prior infections and from prior vaccinations? … I’m going to be optimistic and say I don’t think we’re going to go back to that point.”
The result has been a gradual rise in cases and hospitalizations that never seemed to reach the peaks of this summer’s BA.5 wave and was certainly nothing like the tsunami of illness caused by the original Omicron strain a year ago.
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Pavitra Roychoudhury, director of Covid-19 Sequencing at the University of Washington School of Medicine, said that no variant has taken off at that speed for a few months.
Trevor Bedford, a professor of computational biology at the Fred Hutchinson Cancer Center in Seattle, said XBB.1.5 has a growth rate similar to that of its distant cousin BA.5.
Bedford has pegged its effective reproductive number – the number of new infections expected to be caused by each infected person – at about 1.6, roughly 40% higher than its next closest competitor.
I think it will drive increased circulation in the next few weeks. That increase may not be reflected in case numbers, he pointed out, since more people are testing at home, and their cases may not be counted unless they seek medical care and get a lab test to confirm their results. “So I’d look to hospitalizations in the vulnerable age groups [such as seniors] as better indicator of wave,” he wrote.
Identifying the Omicron Variant of the Covid-19 Viral Hybrid Viruses XBB.1.5, BQ.1, and BQ 1.1
The professors at Columbia University tested viruses with spikes of XBB and XBB, and BQ.1 and BQ 1.1 in the lab, against the blood of people who had been exposed to it. His team also tested 23 monoclonal antibody treatments against these new sublineages.
Ho said Monday that XBB.1.5 was the same story in terms of antibody evasion as XBB.1, which means it has the potential to escape the protections of vaccinations and past infections. It’s also resistant to all current antibody treatments, including Evusheld.
The original Omicron variant was from the Covid-19 viruses and Ho says they have shifted as far from the antibodies we have made to use against them as possible.
The levels of immune evasion could jeopardize the efficacy of the Covid-19 vaccine, according to him. His findings were published in a journal.
This mutation was first flagged by Bloom, who studies the evolution of viruses and viral proteins, as one that could be important for viral fitness. It has been confirmed by Yunlong Cao at Peking University.
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Andrew Pekosz said that public health officials would expect an increase in Covid-19 cases even before they knew about XBB. 1.5. “So whether the increases in Covid cases that are occurring during the holidays are occurring because of the social interactions that people have had or whether they’re specifically related to XBB.1.5 is still something that isn’t clear. Both of those things are probably contributing.”
Most experts said that while they expect that XBB.1.5 has the potential to cause more illness, they don’t expect those infections to necessarily be more severe.
He said that they still give a level of immunity that may not prevent you from getting sick, but it may have some impact on your chances of dying. The most recent data we have shows that the people who have the bivalent vaccine are less likely to die than the people who don’t.
The Americans are slow in getting the new boosters. The data from the CDC shows that 15% of Americans have had an updated booster. Among seniors – those age 65 and older – only about 1 in 3 have had an updated shot.
Experts also note that although antibody treatments won’t work against this sublineage, other antivirals, such as Paxlovid and remdesivir, should still be effective.
There are effective tools to avoid severe Covid-19 infections that include rapid tests and high-quality masks, along with oral antiviral pills and updated vaccines.
“It doesn’t appear to be causing any more severe illness, and so I think that it’s a very different situation circulating today than had it been a year ago,” Osterholm said. I don’t believe that it will take off because of the amount of immunity in the population.
Health experts are concerned over the rapid growth of the Omicron sublineage, but they want the public to not be alarmed and to stay informed.
“We do expect further waves of infection around the world, but that doesn’t have to translate into further waves of death because our countermeasures continue to work,” she said.
She said WHO is working on a risk assessment for this sublineage and hopes to publish it within the next few days. The group’s technical advisers are looking at both real-world data on hospitalizations and lab studies to assess severity.
Covid-19 and its recombination: a new combination of the most evasive Omicron subvariants, XBB
Years of Covid lockdowns took a brutal toll on Chinese businesses. The rapid spread of the virus has deprived them of workers and customers.
The public question its credibility due to the lack of crisis in China where the leadership often brags about its governance.
This mixing, called recombination, happens fairly often among coronaviruses. Scientists have discovered many different forms of the disease, a cause of Covid-19.
According to Thomas Peacock, a professor at Imperial College London, XBB picked up most of the possible genes from the two parents. One of the most evasive Omicron subvariants, XBB, was created by the new combination.