What is the new crown variant virus delta strain?The delta strain of the new crown variant virus has spread to 92 countries. So, what are the characteristics of delta strain? What is the current communication situation? How to prevent?
This strain was first discovered in India in October 2020 and was initially called “double mutant” virus by the media. According to the communiqu of the end of March this year by the Ministry of health of India, the India COVID-19 genomics alliance, composed of 10 laboratories, found in the samples collected in Maharashtra state that the new mutation strains carrying E484Q and L452R mutations may lead to immune escape and infectious enhancement. The mutant strain was named b.1.617 by who and was written in Greek letters on May 31 δ (delta) naming.
Shahid Jamil, Dean and virologist of trividi School of Biosciences of Ashoka University in India, said in an exclusive interview with the Xilong times in India that this mutant strain called “double mutation” is not accurate enough. B.1.617 contains 15 mutations in total, 6 of which occur in spike proteins, of which 3 are more critical: l452r and e484q mutations occur in spike proteins and human cells In the binding region of “angiotensin converting enzyme 2 (ACE2)” receptor, l452r improves the ability of virus to invade cells, e484q helps to enhance the immune escape of virus; the third mutation p681r can also make the virus enter cells more effectively.
The combined effect of these mutations enables the virus to partially avoid some neutralizing antibodies and enhance its infectivity.
Maria van kelkhofer, technical director of the WHO health emergency project, said that alpha was first discovered in the UK（ α） Variant strains have spread rapidly all over the world, and delta strain is easier to spread than alpha strain.
At present, 92 countries and regions have detected the transmission of delta strain, of which 80 countries and regions have found subtype b.1.617.2 and 12 countries and regions have found subtype b.1.617. In May this year, who has listed delta strain as a new crown variant strain that needs attention.
Whether the pathogenicity of delta strain is enhanced? At present, there is no unified view in the scientific community. Antony fudge, director of the National Institute of allergy and infectious diseases, recently said that delta strain has a higher chance of causing severe illness than the most common alpha strain in the United States. A study in Scotland also suggested that delta strain may increase the risk of patients being hospitalized. But there is no consensus Who believes that there is no indication that delta strain will lead to an increase in the death rate of new crown.
The vaccine is still effective
A recent study published in the lancet showed that the neutralizing antibody titer against delta virus strain decreased after human vaccination with the new crown vaccine. However, many experts believe that vaccination is still effective, at least preventing severe diseases and reducing death.
According to a report released by the public health bureau of England in May, researchers analyzed the data from April 5 to May 16 and found that two weeks after the second dose of the new crown vaccine jointly developed by Pfizer Pharmaceutical Co., Ltd. of the United States and new biotechnology company of Germany, the effective rate of preventing symptoms after infection with delta virus is still 88%. If the vaccine is from AstraZeneca pharmaceutical company of the United Kingdom, The effective rate of preventing symptoms after infection with delta virus strain can also reach 60%.
Van kelk Hoffer 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, resulting in the actual loss of efficacy of the vaccine, which is the situation that people need to ensure prevention. Therefore, virus transmission should be avoided and reduced as far as possible, because the wider the virus spreads, the greater the chance of mutation.
Vernita Barr, a visiting professor and immunologist at the India Institute of science and education, stressed that no matter what kind of COVID-19 is targeted, “vaccination always gives you a favorable position to fight infection.”