15 elementary school students in Putian infected with the new crown!

As at 16:00 on September 12, reported a total of Putian new crown virus nucleic acid positive 64 cases, including 32 confirmed cases, asymptomatic infection in 32 cases
.

The case details show that it contains 15 elementary school students

As at 16:00 on September 12, reported a total of Putian new crown virus nucleic acid positive 64 cases, including 32 confirmed cases, asymptomatic infection in 32 cases

Compared with the previous original virus outbreak, the Delta virus has infected more children

Recently, a report was published in Nature magazine to explore the reasons behind it

There are obvious differences between the susceptible populations of the new coronavirus and other viruses
.

More than the number of viruses (such as influenza virus, respiratory syncytial virus) susceptible children plus the elderly

There are obvious differences between the susceptible populations of the new coronavirus and other viruses

According to data collected by the Centers for Disease Control and Prevention (CDC), from March 2020 to the end of August 2021, a total of 3,649 young people younger than 18 years old were hospitalized due to COVID-19 infection in the United States.

In this regard, immunologist Dusan Bogunovic believes that the greatest advantage of adults with viruses is that they have more "experience".
The immune system of adults has seen a variety of similar viruses, so it has a stronger ability to resist
.
However, SARS-CoV-2 disease drug is very new, before that no one saw
.
We can also make further inferences that the virus is very new, and the immune system of
no one child may have a stronger ability to control the virus under natural circumstances .
Source: Nature So, why are children less affected by the new crown? Regarding this issue, the scientific community has conducted a lot of brainstorming: Corollary one, children are less infected .
However, the data proves that this is not the case .
The American Academy of Pediatrics found that as of the end of last month, at least 4.
8 million young people under the age of 21 were infected with the new crown, which accounts for about 15% of all new crown patients .
Therefore, this inference does not hold .
Corollary two, the number of replications of the virus in children is small .
Because the new coronavirus requires ACE2 receptors to enter and further affect cells, some scholars have inferred that the expression level of ACE2 receptors in children may be lower .
Overturned: There is a conflict between different evidence regarding the number of ACE2 receptors in the nose and lungs .
However, in terms of the number of new coronaviruses detected in the upper respiratory tract, there is no significant difference between children and adults .


 
Corollary three, children seem to have colds all year round, and may be more exposed to the coronavirus that causes colds, so they already have corresponding antibodies
.
This is also not true .
There is evidence that adults also have these antibodies in children .
And more importantly, these antibodies have no special protective effect on the new crown .
After these speculations were overturned, Herold began to look for other possible reasons .
Image: REUTERS/Aly Song Herold and her colleagues conducted a trial in which 65 patients were younger than 24 years old, 60 patients older than 24 years old, and patients younger than 24 years old (low age group) had obvious symptoms of new coronary disease Lighter .
After measuring their immune-related cells and antibody levels, it was found that the antibody levels of the two groups of patients were similar, but the acquired immune response-related antibody and cell levels were lower in patients in the lower age group, while the interleukins and interleukins related to the innate immune response were lower.
Interferon levels are even higher .
Herold therefore concluded that children’s acquired immune response is weaker, possibly because their innate immune response is more effective .
Even the overactive acquired immune response in adults may be one of the reasons for the complications of COVID-19 .
COVID-19 Next, Herold and her colleagues try to directly measure the children's innate immune response in the body, they do a nasal swab and throat swabs of 12 children's emergency room, 27 new adult crown infection .
  
    
It was found that the levels of signaling proteins (such as interferons and interleukins) in children's bodies were higher, and the expression of genes encoding these proteins was also higher
.
Yonker pointed out that innate lymphoid cells are the first immune cells that can detect tissue damage and secrete signal proteins.
They can also help innate immune response and obtain immune response .
In an article published on July 4 this year, Yonker and her colleagues found that men have fewer intrinsic lymphoid cells, and in people who are not infected with the new crown, the intrinsic lymphoid cells decrease with age.
This may explain why the severe cases of people infected with the new crown are more likely to occur in elderly men .
In addition, adults with severe diseases and symptomatic children also have lower intrinsic lymphoid cells .
                             Picture: Children infected or exposed to the new coronavirus, the innate immune cell spectrum in the acute and recovery phases.
                                                Picture source: Nature.
Similarly, activated neutrophils (activated neutrophils) can swallow the virus before the virus replicates, which is also a fight against "unfamiliar" Pioneer of the invaders .
Compared with adults, children who have recently been infected with SARS-CoV-2 have a higher level of activated neutrophils, and the effects of these cells become worse with age .
There are also data showing that the epithelial cells tested in the nose may also be involved in the rapid immune response to the virus .
In children, epithelial cells contain a large number of receptors that can recognize pathogens .
Specifically, 
    The expression of genes that compile MDA5 is higher in children, and MDA5 is a receptor that can recognize SARS-CoV-2
.
Roland Eils, a scientist in the field of computational genomes, further added that these cells can quickly stimulate the production of interferon after identifying the virus .
The level that takes two days to reach in an adult can be reached on day 0 in a child .
Child immunologist Isabelle Meyts said that children with congenital immune system defects are more likely to become severely ill, while children with acquired immune system defects that do not produce antibodies are less affected by the new crown .
Therefore, she concluded that the fight against the new coronavirus is not the acquired immune system, but the innate immune system .
However, just like the innate immune system deficiency, the innate immune system is too active .
Studies have found that children with Down syndrome are more likely to develop severe illness after being infected with the new crown.
Meyts said that may be because the extra chromosomes have some genes related to type I interferon response .
Therefore, whether the innate immune system is too strong or too weak is not good, and it must be exactly on the spot .
However, this difference in immune response is only the appearance, what causes this difference? Laura Vella, an immunologist and pediatric epidemiologist, suggested that this may be the result of a combination of multiple factors .
Some scholars believe that this is related to the "antigenic sin phenomenon .
" That is, adults have been exposed to more coronaviruses.
Therefore, when encountering a new coronavirus, the adult immune system will use the immune memory that has been generated to produce antibodies against the viruses that have been encountered.
No effect .
The discovery of immunologist Amy Chung in the experiment proves this:    
  Adults have more antibodies against SARS-CoV-2 that can also fight against other coronaviruses, while children have a broader spectrum of antibodies that tend to fight against all coronaviruses
.
                                                           Picture: Different immune connections between children and adults                                                            Picture source: Nature However, there are still contradictions between different data regarding the current long-term response to the new crown .
A recent study mentioned that 14% of young people still have multiple symptoms 3 months after diagnosis .
The diagnosis is that some children who are completely healthy except for the new crown have the pediatric multiple system inflammation syndrome (MIS-C).
The ratio of this complication is about 3 / 10,000.
It is characterized by a good initial response and a series of symptoms suddenly occur a month later.
e.
g.
heart failure , abdominal pain, conjunctivitis .
In this regard, pediatric and infectious disease scientist Michael Levin gave his own conjecture: MIS-C may be caused by the response of super-large antibodies or T cells .
However, the distinguishing factors for which children are easy to get MIS-C and which children are not easy to get MIS-C are not yet known .
Heart failure Now, with the emergence of the Delta variant virus, the proportion of children infected and hospitalized has begun to increase.
This result may be related to the greater contagiousness of the Delta variant virus and the majority of adults being vaccinated .
    
                  Picture: A child receives treatment for COVID-19 in Istanbul, Turkey in April.
Credit: Sebnem Coskun/Anadolu Agency/Getty The recent surge in children’s new crown cases in the United States, the latest report released by the American Academy of Pediatrics shows that as of August 26 Within a week, about 204,000 children in the United States were diagnosed with the new crown virus, accounting for 22.
4% of the confirmed cases of the new crown reported in the United States that week
.
                                                    doi.
org/10.
15585/mmwr.
mm7036e1external icon On September 3, according to a report released by the US CDC, from late June to mid-August, the weekly COVID-19 hospitalization rate for children and adolescents in the United States increased nearly five times.
This is consistent with the accelerated spread of delta in the United States .
According to the report, the hospitalization rate of adolescents who have not received the new crown vaccine is 10 times higher than that of fully vaccinated adolescents .
According to the article, as of August 14, the hospitalization rate for children with new coronary pneumonia was 49.
7 per 100,000 children.
Among them, the hospitalization rate for children under 4 was the highest (69%), followed by adolescents aged 12-17 (64%) .
The new crown pneumonia in mid-August, due to the variation of the spread delta, hospital admissions began to rise, many students return to school, children and adolescents and the number of hospitalizations compared with the end of July, mid-August increased nearly 5-fold, while the number of hospitalized children below the age of 4 has increased by 10 times over the same period .
  
 
                                           DOI: http://dx.
doi.
org/10.
15585/mmwr.
mm7036e1external icon The American Academy of Pediatrics reported at the end of August that child deaths caused by new coronary pneumonia are still “uncommon”
.
Among the reported states, children accounted for 0.
00%-0.
24% of all COVID-19 deaths.
Seven states reported zero child deaths.
According to the published report, from the data collected in 45 states, 0.
00% Up to 0.
03% of children's new crown cases have died
.
According to data from the HHS Unified Hospital Data Monitoring System, compared with states with higher vaccination rates in August, in states with lower COVID-19 vaccination rates, children’s emergency and hospitalization rates were 3.
4 and 3.
7 times higher, respectively .
The US CDC pointed out that following its recommendations on universal wearing of masks, maintaining social distancing, and vaccinating at school is still the best way to prevent the spread of the virus among children .
As the new crown epidemic continues, researchers are beginning to worry that the virus may evolve the ability to fight children's innate immunity .
This is not groundless, the previous Alpha variant has evolved a way to suppress innate immunity .
Now, everyone is beginning to worry that the Delta variant has also evolved the same ability .
Herold commented on this that almost all viruses will develop methods to attack the innate immune system, and the new coronavirus is no exception .
Now, children can still rely on the innate immune system to defeat the new coronavirus, but who knows how long this can last? Reference link: https:// Leave a message here