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What is the delta strain of the new crown mutant virus??
Time:2021-06-28
Views:970
What is the delta strain of the new crown mutant virus ？
On June 22, the World Health Organization stated on the 21st that the delta strain of the new coronavirus mutant has now spread to 92 countries. So, what are the characteristics of the Delta strain? How is the current spread? How to prevent it?
1. Increased infectiousness
This strain was first discovered in India in October 2020 and was initially called a "double mutant" virus by the media. According to the announcement by the Ministry of Health of India at the end of March this year, the "India New Coronavirus Genomics Alliance" composed of 10 laboratories found in samples collected in Maharashtra that this new mutant strain carries E484Q and L452R mutations. , May lead to immune escape and increased infectivity. This mutant strain was named B.1.617 by the WHO and was named with the Greek letter δ (delta) on May 31.
Shahid Jamil, the dean of the Trivedi School of Biological Sciences at Ashoka University in India and a virologist, said in an interview with the Shillong Times of India that this mutant strain called "double mutation" is not accurate enough. B. 1.617 contains a total of 15 mutations, of which 6 occur on the spike protein, of which 3 are more critical: L452R and E484Q mutations occur on the spike protein and the human cell "Angiotensin Converting Enzyme 2 (ACE2)" receptor In the bound region, L452R improves the ability of the virus to invade cells, and E484Q helps to enhance the immune escape of the virus; the third mutation P681R can also make the virus enter the cell more effectively.
The combined effect of these mutations enables the virus to partially avoid some neutralizing antibodies and increase infectivity.
2. The spread has been widespread
Maria Van Kelkhoff, the technical leader of the WHO health emergency project, said that the alpha (α) variant strain first discovered in the UK has spread rapidly around the world, and the delta strain is more easily spread than the alpha strain .
At present, 92 countries and regions have detected the transmission of Delta strains, of which 80 countries and regions have found B.1.617.2 subtypes, and 12 countries and regions have found B.1.617 subtypes. In May of this year, the World Health Organization has listed the Delta strain as a new coronavirus mutant strain that "needs attention".
Is the pathogenicity of the delta strain enhanced? At present, the scientific community does not have a unified view. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, recently stated that the Delta strain is more likely to cause severe illness than the Alpha strain, which is currently the most common in the United States. A study in Scotland also suggested that the delta strain may increase the risk of patients being admitted to the hospital. However, the WHO believes that there is no indication that the Delta strain will cause the death rate of the new crown to rise.
3. The vaccine is still effective
After the human body is vaccinated with the new crown vaccine, the titers of neutralizing antibodies produced against the Delta strain have decreased. However, experts in many countries believe that the current vaccination is still effective, at least it can prevent severe illness and reduce deaths.
The Public Health Agency of England issued a report in May that researchers analyzed the data between April 5 and May 16 and found that the second dose of the new crown vaccine jointly developed by Pfizer Pharmaceuticals Co., Ltd. and German Biotech Co., Ltd. was vaccinated for two weeks. Later, the effective rate of preventing symptoms from being infected with the Delta strain is still 88%. If you are vaccinated with a vaccine from the British AstraZeneca Pharmaceutical Company, the effective rate of preventing symptoms after infection with the Delta strain can reach 60%.
Van Kelkhover warned that although the vaccine is still effective against the current virus, there may still be a series of mutations in the virus in the future, which will cause the vaccine to actually lose its effectiveness. This is exactly what people need to ensure prevention. For this reason, the spread of the virus should be avoided and reduced as much as possible, because the wider the virus spreads, the greater the chance of mutation.
Vineta Barr, a visiting professor and immunologist at the Indian Institute of Science and Education, emphasized that no matter what kind of new coronavirus is targeted, "vaccination always puts you in a good position to fight infection."
4. The delta strain spreads rapidly, the World Health Organization: wear a mask after getting a vaccine
On June 25th, in view of the rapid spread of the "Delta" strain of the new crown virus, the World Health Organization urged people who have been vaccinated against the new crown to continue to wear masks, maintain social distancing with others, and avoid going to crowded places.
WHO officials believe that even if they are vaccinated, they should not take risks, because there are still a large number of people around the world who have not been vaccinated, and these people are prone to carry the more transmissible "delta" variant virus. |Howweld
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