The annoying hits from the omicron strains keep coming, with each aftermath more contagious than the last.
Just weeks after the BA.2 subvariant of omicron became dominant in much of the United States and many other countries, the BA.4 and BA.5 strains took over across the country and now appear in more than 70 percent of the samples.
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–The two strains are often lumped together because they have similar mutations in their spike proteins, which stick to human cells. According to CDC data, BA.5 is outperforming its sister.
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–Many readers are aware of several recent cases among friends, family, and co-workers. Some scientists estimate that the current wave of cases is the second largest in the entire pandemic.
We’re going to delve into why these variants are more contagious, what kind of symptoms they cause, and how public health officials are evaluating the recent turn of events.
How do they work
The main advantage of BA strains, especially the newer ones, seems to be their ability to infect people who have already been vaccinated, or who have already had covid, or both. This is a huge advantage, given that much of the world already has some form of immunity. BA.4/5 are significantly more infectious than BA.2, which was itself more contagious than omicron.
“The SARS-CoV-2 omicron lineage continues to evolve, successively producing subvariants that are not only more transmissible, but also more evasive to antibodies,” concludes a new study in Nature.
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–“They are the Houdini of Covid,” Peter Chin-Hong, an infectious disease specialist at the University of California, San Francisco, told my colleague Dani Blum. “They are the escapism artists.”
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–Some patients are reinfected as little as two to three months after being infected, said Stuart Campbell Ray, a professor of medicine at Johns Hopkins Medicine.
Symptoms
Experts state that the subvariants present symptoms similar to those of omicron, such as cough, runny nose, sore throat, fatigue, headaches and muscle aches. Patients are less likely to lose their sense of taste and smell, or experience shortness of breath, Chin-Hong said.
People tend to experience upper respiratory symptoms, “from the vocal cords to the tip of the nose,” said Joseph Khabbaza, a pulmonary and critical care physician at the Cleveland Clinic. Khabbaza has treated many patients with severe sinus congestion and a sore throat so bad they thought they had strep throat.
As is often the case with variants of the coronavirus, it is not clear whether BA.4 and BA.5 are more serious than their predecessors, or simply more contagious. The answer lies in the demographics of a given population and in the combination of vaccination and immunity.
New deaths have remained below 400 a day on average, according to data from state and local health agencies. This is a fraction of the thousands seen daily during the winter peak of omicron.
“Fortunately, other mechanisms of the immune system are still working to reduce serious illness,” said Katelyn Jetelina, who writes the newsletter Your Neighborhood Epidemiologist.
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–“The deaths we’re seeing are generally among people who are elderly, frail, have many comorbidities who have been heavily vaccinated, or people who are not vaccinated,” said Rochelle Walensky, the director of the Centers for Disease Control and Prevention. , At the end of june.
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–Tests
If only public data were looked at, it might be hard to tell any difference. The average number of new confirmed cases each day has barely budged for weeks, hovering between 95,000 and 115,000 daily in June.
But a closer look shows that we are most likely experiencing a surge of cases in the dark: many public testing centers are closingand many states have also stopped offering daily data updates, creating a more nebulous picture of the virus situation across the country.
“One of my favorite lines from someone at the CDC was, ‘You don’t have to count raindrops to know how hard it’s raining,’” Walensky said.
Adam Pasick runs the Times’ newsletters, including The Morning, DealBook, and temporary newsletters like Coronavirus Briefing. @adampasick
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