What does the Delta variant mean for children and Covid?


it has been Been said countless times Public health numbers with politician, And magazine Like this, Covid-19 is now an unvaccinated epidemic. This line is easy to write because it is true. Breakthrough infection among vaccinated people is a problem, and the virus lingers on the edge of our collective immunity. But serious illnesses and deaths are almost entirely concentrated on those who have not been vaccinated.

But who are those who have not been vaccinated? They are getting younger and younger. The largest group is young children, that is, children under the age of 12, because they have not been approved to be vaccinated. But in older children, the situation is not much better. In the United States, only one-third of children between 12 and 15 years old are vaccinated. According to the numbers The data collected by the Centers for Disease Control and Prevention is still below average for people in their teens and twenties. So it’s not surprising that 22% of the U.S. cases reported in the third week of August, a total of 180,000 cases, Diagnosed in children, The overall share since the beginning of the pandemic is 14%. The weekly numbers are twice as high as those at the beginning of the month, which puts pressure on pediatric departments across the United States, especially in places where highly infectious Delta mutations are rampant.

Abdallah Dalabih, an intensive care physician at Arkansas Children’s Hospital, said: “We saw the peak when people started taking off their masks and socializing again.” The only pediatric ICU in the state The number of Covid-19 hospital admissions surged in early August and has remained stubbornly high.

Kofi Asare-Bawuah, a pediatrician at CoxHealth in Springfield, Missouri, said: “We all think Covid is over, so unfortunately, it didn’t stop people from interacting a lot this summer.” The Ozark area in July Witnessed one of the earliest delta waves in the United States, and now it has also appeared Rising MIS-C cases, Some young people develop inflammatory immune diseases a few weeks after infection. In recent weeks, Asare-Bawuah’s team has sent three children with life-threatening cases to a larger hospital in St. Louis for treatment.

David Fisman, an epidemiologist at the University of Toronto, said this is an exhausting reality that runs counter to the idea that the pandemic should end. “We are all fed up with all of this,” he said, pausing to admit that his 9-year-old daughter had stinky sympathetic eyes across the room and she was also very tired of the pandemic news. This is also a confusing reality. The pandemic rules that were entrenched 18 months ago are roughly as follows: Young people and the less vulnerable should stay at home and take other precautions to protect the elderly and people with pre-existing health conditions. This understanding stems from the silver lining of the pandemic: young people are least likely to develop serious illnesses that lead to hospitalization or death—an unusual pattern of respiratory diseases that usually affects children and the elderly.

Experts such as Fisman worry that as transmission between children increases, fatigue and a lack of attention to children’s risks will lead to fewer preventive measures. “I think older people have a lot of selfish concerns about risk,” he said. Maybe we dropped the guards a bit too fast, it’s time for some kind of recalibration. Here are some things to know:

Why does the virus not affect children as much as adults?

In recent months, researchers studying the immune system have begun to feel more confident in certain explanations. One difference is that when the Covid-19 infection begins, the children’s immune systems seem to be more combative. Kerstin Meyer, chief scientist at the Wellcome Sanger Institute, explained that this immune response starts with the production of antiviral proteins called interferons, which recruit a large number of immune cells to the nose. Who learned The difference between the response of adults and children. Among the elderly, a feature of Covid-19 infection is that these initial warning signs are often suppressed, thereby preventing the intensification of critical early responses. This allows the virus to multiply rapidly in the upper respiratory tract and then spread deeper into the lungs, where it can cause more serious diseases. But in children, “this viral sneaking is prevented,” Meyer said. Cells in the nose and throat seem to be more likely to respond quickly, so the infection usually ends before mild symptoms appear.

But what if this can’t kill it in the bud? The children still seem to have an advantage.The innate immune response was quickly added by an adaptive response-a force that recruits and reproduces specific cells, such as B and T cell, To fight against specific pathogens. One theory is that a younger body has a more malleable immune system. In adults, these B cells and T cells have adapted to previously seen infections, but when faced with a new pathogen (such as SARS-CoV-2), the number of pathogens that can be used to learn new techniques decreases. In some cases, the body of an adult will recruit immune cells that are not good for work. This is a wrong response. In the worst case, it may cause uncontrolled effects, cause damage to the body, and fail to clear the virus. Young people have more diverse “naive” immune cells, making them more likely to produce antibodies against new infections. They learn quickly, like a child listening to a new language.

Does Delta make children sicker than other variants?

So far, there is little evidence that Delta variants are more harmful to children than adults. According to the CDC, there is some evidence that delta infections are more serious in all age groups, but the agency has not yet provided a specific classification of children. In Ontario, Fisman has been tracking the hospitalization rate of young people, and children under the age of 10 who are infected with Delta are more than twice as likely to be hospitalized as children who are infected with other variants. But the data is still relatively scarce—in the province, there are 1,300 cases of children under 10, and only 26 are hospitalized—there are too few cases to estimate the relative risk of admission to the ICU or death. But as more data emerges, Fisman’s confidence in his conclusions is rising. “The risk of keeping kids away from this is higher,” he said.

Fisman added that the bigger question is how fast Delta can move among unvaccinated people. According to the Centers for Disease Control and Prevention, the hypothesis that the arrival of this variant means that the hospitalization rate for children with Covid has doubled-the hospitalization rate for children under 18 before the arrival of Delta Air Lines was less than 1%. This is still a relatively small number. But as the virus now spreads at a more aggressive rate, the ever-increasing denominator — the total number of cases — becomes meaningful. “This means that the number of rare events is higher,” Viessmann said. “This is the biggest worry.”


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