COVID-19 Warning! Researchers Say SARS-CoV-2 Mutating Rapidly. Infection Capability and Evading Host Immunity Being Enhanced
: Chinese researchers are saying that the SARS-CoV-2 coronavirus has gone thru six major gene modifications along with thousands of smaller codon changes since January that seems to be enhancing its ability to infect and evade the human immune system. The researchers are saying that at the moment the US and Europe are the major sites for virus mutations but strangely there seems to be no mention or studies focusing on this area while others suspect there could be cover ups. Interestingly many Western genetic research facilities keep on saying that the SARS-CoV-2 coronavirus has not mutated or that it has mutated slightly but it not becoming potent despite emerging evidence.
These mutations also have very important implications about the effectiveness of the vaccines that are under development.
The research findings that are being peer reviewed are at the moment published on a preprint server. https://www.biorxiv.org/content/10.1101/2020.06.16.154591v1
The mutation pattern of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is constantly changing with the places of transmission, but the reason remains to be revealed.
The study comprehensively analyzed the potential selective pressure of immune system restriction, which can drive mutations in circulating SARS-CoV-2 isolates. The results showed that the most common mutation sites of SARS-CoV-2 proteins were located on the non-structural protein ORF1ab and the structural protein Spike. Further analysis revealed mutations in cross-reactive epitopes between SARS-CoV-2 and seasonal coronavirus may help SARS-CoV-2 to escape cellular immunity under the long-term and large-scale community transmission. Meanwhile, the mutations on Spike protein may enhance the ability of SARS-CoV-2 to enter the host cells and escape the recognition of B-cell immunity.
According to the research lead by Professors Dr Qiu Tianyi and Dr Leng Qibin from the two top epidemic research centres in China: State Key Laboratory of Respiratory Disease in Guangzhou and the Shanghai Public Health Clinical Centre, the novel coronavirus has gone through rapid mutations and may spread for a longer time than expected. Since the start, the virus has gone through at least six major changes in its genes that boosted infectivity and “immune escape” ie its ability to escape the detection and attack by the human immune system.
It was said that most of these mutated strains occurred in America and Europe.
The SARS-CoV-2 coronavirus uses the spike protein to infect human cells. The spike protein binds with a molecule called angiotensin-converting enzyme 2 (ACE2) in host cells.
The researchers identified three mutations R408I, N439K and G476S that improved the binding strength.
One major mutation was in the in the N439K gene, which added a chemical bond between the ACE2 and the spike protein enhancing its binding and infection capability.
The three other mutations D614G on S protein, P4715L on ORF1ab and R203K on N protein targeted the immune system.
A major one of these mutations, R408I was such that it could destroy an ionic bond between the virus a
nd an antibody that is supposed to neutralize Sars-CoV-2.
Significantly, these mutations were in a way similar to those that occurred in human immunodeficiency virus (HIV) and influenza, which dodge immune attack with fast mutation.
Dr Tianyi told Thailand Medical News, “This means that even if the effective vaccine could be developed for current circulating Sars-CoV-2, the rapid, immune escape trend mutations will cause the ineffectiveness of the vaccine in a short time.”
Interestingly many vaccine developers refused to comment publicly on this findings when Thailand Medical News contacted them as most probably they do not want their stock prices or fundings to be affected.
Past studies had found that an average adult had a “cold” caused by other coronaviruses every two years. The human immune response could have learned from these earlier infections and imposed a selective pressure on some common genes that drove the rapid evolution of Sars-CoV-2, according to the Chinese researchers.
A study by American scientists estimated the pandemic would end next year if humans could establish long-lasting immunity against the virus. However if the immunity was short-lived, the outbreak would return every year, said the researchers led by Professor Marc Lipsitch from the Harvard TH Chan School of Public Health.
Another research by a team in Wuhan reported that they failed to find long-lasting antibodies among medical workers exposed to the virus at the early stage of outbreak. They warned that humans might never develop immunity against Covid-19. https://www.thailandmedical.news/news/breaking-covid-19-immunity-new-study-that-is-yet-to-be-peer-reviewed-says-humans-may-never-develop-immunity-against-covid-19
This new study will increase the understanding of the evolutionary direction and warn about the potential immune escape ability of SARS-CoV-2, which may provide important guidance for the potential effective vaccine design.
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