Vaccines may need regular updates as coronavirus evolves, scientists say

BERLIN, March 27: Scientists have assessed the course of evolution of the novel coronavirus and predicted that COVID-19 vaccines currently in use around the world may require regular updates to counter new variants of the virus capable of escaping to the body’s protective antibodies.

The study, published in the journal Evolution of the virus, assessed whether, in the long term, the SARS-CoV-2 virus is likely to demonstrate an immune evasion capacity comparable to that of influenza viruses.

As part of the research, virologists from Charite – Universitatsmedizin Berlin in Germany studied the genetic evolution of the four currently known “ common cold ” coronaviruses, in particular the two oldest viruses, 229E and OC43.

They tracked the changes in the spike protein of these coronaviruses, which allow them to enter host cells, around 40 years ago.

Based on the analysis, scientists found a feature common to both the coronavirus and the influenza virus: All three had a pronounced ladder-like shape in their evolutionary trajectories.

“An asymmetric tree of this type is probably the result of the repeated replacement of one variant of the circulating virus with another that had a fitness advantage,” said the study’s first author, Wendy K Jo.

According to Jo, this is evidence of “antigenic drift,” an ongoing process involving changes in surface structures that allow viruses to evade the human immune response.

“This means that these endemic coronaviruses also elude the immune system, just like the flu virus. However, we also have to look at the speed at which this evolutionary adaptation occurs, ”she added.

Scientists have said that the genome of the new coronavirus is currently estimated to change at a rate of around 10 mutations per 10,000 basic molecules per year, which means the rate at which it evolves is considerably higher than that of endemic coronaviruses. . – PTI

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