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SARS survivors can have super immunity after receiving COVID-19 vaccines
SARS survivors can have super immunity after receiving COVID-19 vaccines. Recently, a new study shows that people who have had SARS after being vaccinated with the COVID-19 vaccine seem to have acquired a kind of “super immunity”-able to resist all the mutant strains of the COVID-19 virus that are currently circulating.
People who were infected with severe acute respiratory syndrome (SARS) nearly two decades ago will have a strong antibody response after being vaccinated with the COVID-19 vaccine. Their immune system can resist a variety of SARS-CoV-2 variants, as well as related coronaviruses found in bats and pangolins, to achieve cross-protection.
The Singapore team of a small study published in “The New England Journal of Medicine” stated that the results of the study provide hope for the development of vaccines, which can prevent all new SARS-CoV-2 variants and other possible future pandemics. Coronavirus. Recently, a researcher published an article titled “Decades-old SARS virus infection triggers potent response to COVID vaccines” on Nature.
David Martinez, a viral immunologist at University of North Carolina at Chapel Hill, said the study is a concept that “proves that a human pan-coronavirus vaccine is possible.” This is a very unique and cool study, but it should be noted that it does not include many patients.
The new coronavirus is similar in structure to the severe acute respiratory syndrome (SARS) virus, and belongs to the Sarbecovirus subgenus under the genus B coronavirus. Including the virus that causes SARS (called SARS-CoV), and the closely related bat and pangolin coronavirus. Sarbecovirus uses the known spike protein to bind to the ACE2 receptor on the host cell membrane and enter the host cell. They can spread from animals to humans, just as they did in the current pandemic and the SARS outbreak in 2002-2004. SARS has spread to 29 countries. Martinez said: “This has happened twice in the past two decades, and this is a strong reason-that this is a group of viruses that we really need to pay attention to.”
Last year, Wang Linfa, a virologist at the Duke National University School of Medicine in Singapore, who led the latest study, sought out SARS survivors to see if they could provide clues on how to develop vaccines and drugs for the new coronavirus. He detected neutralizing antibodies in their blood, which prevented the original SARS virus from entering the cells, but did not affect SARS-CoV-2, which surprised him because of the close connection between the viruses.
The study, conducted by the School of Medicine of Duke National University of Singapore and the National Center for Infectious Diseases of Singapore, respectively examined 10 unvaccinated SARS survivors, 10 unvaccinated COVID-19 survivors, and 10 healthy individuals who had completed Pfizer vaccination. Serum samples of participants, 10 recovered patients with the new coronavirus who completed vaccination, and 8 recovered patients with SARS who completed the new coronavirus vaccination were studied.
Studies have found that only the serum of SARS patients who have completed the new coronavirus vaccination have antibodies that can effectively neutralize SARS virus, new coronavirus and other similar new coronaviruses at the same time. Experimenters in other groups will only have extremely high neutralizing antibodies against SARS and similar viruses, or new coronaviruses and similar viruses, and have relatively low levels of neutralizing antibodies against another type of virus.
Wang Linfa said that researchers speculate that this is related to the cross-protection effect of neutralizing antibodies. When the human body is infected with a virus or vaccinated, antibodies will neutralize immunodominant epitopes. The antibodies produced after infection with SARS and vaccinated with the new coronavirus vaccine can neutralize other epitopes and have an effect on the same type of virus. This discovery provides the scientific basis for the development of the third-generation comprehensive new coronavirus vaccine. These vaccines can not only fight against the new coronavirus and different variant strains, but also provide protection against other variant strains or subgenus coronaviruses called Sarbecovirus in the future. It can also produce antibody drugs that can be used for treatment.
Eight vaccinated study participants recovered from SARS about 20 years ago. Even if they received only one dose of the vaccine, they produced very high levels of neutralizing antibodies against the two viruses. They also produced extensively neutralizing antibodies against three SARS-CoV-2 variants that are worrying in the current pandemic-α, β and Delta, as well as five coronaviruses from bats and pangolins, which also belong to the Sarbecovirus subgenus. . Even in blood samples collected by people infected with the new coronavirus, no such strong and extensive antibody response has been observed.
Researchers believe that the reason why the COVID-19 vaccine can produce such a wide range of protection is because the COVID-19 vaccine can awaken the immune system’s “memory” of the SARS virus area, which also exists in SARS-CoV-2, and may also exist in many other Sarbecoviruses. middle.
Daniel Lingwood, an immunologist at MGH in Boston, Massachusetts Institute of Technology, and Harvard University’s Lagon Institute, said that the coronavirus found in bats may cause future pandemics, so a wide range of neutralizing antibodies has been produced to defend against some of them. The fact of the virus is “encouraging.” But the researchers said that it is not yet clear how long this protection will last.
Christopher Barnes, a structural biologist at Stanford University in California, added that a broadly effective vaccine against Sarbecoviruses can be administered to the general population in high-risk areas close to the host animal, thereby limiting the potential spread of these viruses in the population.
Barton Haynes, an immunologist at the Duke University School of Medicine in Durham, North Carolina, said the study raises a question: if people vaccinated with the COVID-19 vaccine are vaccinated with a booster vaccine against the original SARS virus, will they have a similar response . This may protect them from SARS-CoV-2 and other new variants of Sarbecoviruses. Wang Linfa said that preliminary studies on rats have shown that this is possible.
However, the latest research has not determined exactly which parts of the virus will induce a broad immune response, which is required for the development of a vaccine. Martinez said: “This is the’biggest problem.’ If a certain area of the virus exists not only in Sarbecoviruses, but also in the entire coronavirus population, then it is possible to develop a vaccine against all coronaviruses.”
Several research groups have identified specific antibodies that prevent SARS-CoV-2 and other Sarbecoviruses from spreading in cells. Others are already developing pan-coronavirus vaccines and have synthesized ingredients that have a strong protective effect on monkeys and mice.
For example, Haynes and his colleagues have developed a protein nanoparticle in which 24 SARS-CoV-2 spike protein fragments, called receptor binding domains, are embedded in them, which are key targets for antibodies. They found that in monkeys, the level of SARS-CoV-2 antibodies induced by nanoparticles was much higher than that of Pfizer vaccine. It also induced cross-reactive antibodies against the original SARS virus, bats and pangolin Sarbecoviruses.
Martinez and his colleagues used a vaccine made from a combination of spike proteins from different coronaviruses to induce these broadly reactive antibodies in mice. But Martinez said: “The latest research shows that this complex spiny chimera may not be necessary. A similar protective response can simply be induced by the spike protein of the original SARS virus.”
Wang Linfa said that he is already studying potential vaccines against a variety of Sarbecoviruses, and now he hopes to find more survivors of the SARS outbreak in 2002-2004 to conduct larger studies, including testing their response to other new coronavirus vaccines.
(source:internet, reference only)