Science and Technology Daily reporter Zhang Jiaxin
In recent days, the epidemic situation has rebounded severely in many parts of the country, and the prevention and control situation is grim
The head of the World Health Organization (WHO, hereinafter referred to as "WHO") said on the 30th local time that the number of confirmed cases and deaths caused by new coronary pneumonia continues to rise globally, mainly due to the highly contagious new crown Caused by the virus mutant strain Delta
Why is Delta so "poisonous"? What kind of mutation does it have? How infectious is it?
Why is Delta so "poisonous"? What kind of mutation does it have? How infectious is it? Delta virus load exceeds 1,000 times the original strain
Delta virus load exceeds 1,000 times the original strain Dr.
She said that experts have found that individuals infected with Delta have a higher viral load
Rochelle Varensky, director of the US Centers for Disease Control and Prevention (CDC), told the New York Times that new research shows that people who have been infected with the Delta strain and also vaccinated carry a lot of the virus in their noses and throats.
New York Times The Los Angeles Times reported on the 30th that people infected with the Delta strain have 1,000 times more virus particles in the upper respiratory system than people infected with the original coronavirus that initially caused the pandemic
On the severity, the Van Hoff stressed that in some countries affected by the variation of the number of hospitalizations has increased, "but we have not seen the rise in mortality"
The P681R mutation makes the Delta strain more susceptible to infecting cells
The P681R mutation makes the Delta strain more susceptible to infecting cells Dr.
The "Nature" magazine website issued an article on the 28th that the outer surface of each new coronavirus particle is dotted with 24-40 randomly arranged spike proteins, which is the key to its binding to human cells
Delta strain has many mutations in the S1 subunit, including three mutations in RBD
According to the American Society of Microbiology, another mutation (located on a unique spike protein) in a place called the furin cleavage site may also make it easier for the virus to infect cells
There is evidence that a mutation in Delta called "P681R" promotes furin-mediated cleavage of the spike protein, accelerates the fusion of virus cells and human cells, and enhances the virus's ability to neutralize antibodies.
Delta strain is as infectious as chickenpox
Delta strain is as infectious as chickenpox The Washington Post quoted an internal report from the CDC on the 30th, stating that the delta mutant strain of the new coronavirus is as contagious as chickenpox
Eight or nine According to the report, this variant is also more likely to break through the protection provided by the vaccine
The report cited recent unpublished data obtained from the epidemic investigation and combined data from external research showing that people who have been infected with the Delta strain and have been vaccinated may spread the virus as easily as people who have not been vaccinated
CNN reported on the 30th that a research team from the British infectious disease modeling agency stated that data showed that the transmission rate of the delta virus variant strain is 40-60% higher than that of the alpha variant strain
.
Chi Chunhui, director of the Center for Global Health at Oregon State University in the United States, said that for the previous variants, it takes about 6 days for a person to produce enough virus to infect others after the initial infection
.
The Delta mutant shortened the timeline to only 4 days, allowing it to spread in the community at an unprecedented rate
.
Vaccination is still a response
Vaccination is still a response No vaccine is 100% effective
.
Therefore, despite the vaccination, there are still more cases of breakthrough infections (i.
e.
infected persons who have completed vaccination)
.
The latest CDC study on the 30th showed that 74% of the infected people in the outbreak of the new crown in Massachusetts in the United States have been fully vaccinated
.
The CDC stated that it needs to continuously monitor the effectiveness of the vaccine against the variants
.
Tests conducted in a laboratory petri dish show that, theoretically, the immune response generated by the vaccine should be strong and broad enough to deal with "delta
.
"
CNN reported that infectious disease experts generally believe that the answer to the spread of Delta strains and other viruses is more vaccination
.
"If we have more and more people vaccinated, we will win this fight against the epidemic," Varensky said
.
Dr.
Van Khoff of the World Health Organization reminded that although there are some data indicating that people who have been vaccinated may be infected and spread this mutant virus, this possibility is greatly reduced after the second dose of the vaccine is fully effective.
.
She also said that the delta strains are not specifically targeted at children.
As long as the mutated virus is still spreading, they will infect anyone who has not taken proper precautions
.
Focus on the new crown pneumonia epidemic
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