The study, published in the journal Virus Evolution, assessed whether, over the long term, the SARS-CoV-2 virus is likely to demonstrate an immune evasion capability on par with that of influenza viruses.
Scientists have studied the evolution of coronaviruses and predict that the COVID-19 vaccines currently in use worldwide needs constant updates to combat new variants.
The study, published in the journal Virus Evolution, looked at whether the SARS-CoV-2 virus can demonstrate long-term immune evasion like that of the influenza viruses.
In the study, virologists from Charite – Universitatsmedizin Berlin in Germany learned about the genetic evolution of the four common ‘cold’ coronaviruses, mainly the two longest strains, 229E and OC43.
They discovered mutations in the Spike protein structure of these coronaviruses, which enable them to enter host cells, approximately 40 years into the past.
In the study, scientists discovered a feature that is common to both coronavirus and influenza virus, all of which have a similar ladder-like shape in their evolutionary paths.
“An asymmetrical tree of this kind likely results from the repeated replacement of one circulating virus variant by another which carried a fitness advantage,” explained the study’s first author, Wendy K. Jo.
Jo explained the evidence of the “antigenic drift”, which is an ongoing process that involves changes in the surface structures which enable viruses to evade the human immune response.
“It means that these endemic coronaviruses also evade the immune system, just like the influenza virus. However, one also has to look at the speed with which this evolutionary adaptation happens,” she added.
Scientists have suggested that the genome of the new coronavirus is currently estimated to mutate at a rate of 10 times per 10,000 molecules a year, meaning that the current mutation rate is much higher than that of the endemic coronaviruses.
“This rapid genetic change in SARS-CoV-2 is reflected in the emergence of numerous virus variants across the globe,” explained study co-author Jan Felix Drexler.
“This, however, is likely due to the high rates of infection seen during the pandemic. When infection numbers are so high, a virus can evolve more rapidly,” Drexler added.
Based on the evolutionary patterns observed in known cold coronaviruses, scientists believe that SARS-CoV-2 will slowly start evolving once the virus dies.
“Once a large proportion of the global population has developed immunity either as a result of infection or through vaccination. We expect therefore that COVID-19 vaccines will need to be monitored regularly throughout the pandemic and updated where necessary,” Drexler explained.
According to the virologists, vaccines are likely to remain effective for longer once the pandemic reaches this stable situation.
