As well as sounding a warning that more dangerous variants of Covid will continue to emerge well into the future, the finding also provides a path toward preventing them spreading from country to country.The Melbourne team led by Dr Sebastian Duchene found the SARS-CoV-2 virus was able to mutate into a more lethal new variant in just six weeks, despite other viruses typically taking a year or more to undergo such changes.Although SARS-CoV-2 generally evolves at a similar rate to other viruses and slower than the flu, Dr Duchene said it has the ability to temporarily undertake “short-lived mutational bursts” when it strikes an unvaccinated or non-immune population, allowing it to speed up its evolution “like someone pumping the accelerator on a car”.“If you infect a host over a long time, there will be this evolutionary arms race, which means the virus will be forced to innovate a lot and that innovation is ultimately mutation,” Dr Duchene said.“It will start coming up with a lots mutations to evade the immune system within one host … then when it comes out from this host who was infected for a long time to eventually infects somebody else, you have a very different virus because it has undergone this evolutionary arms race for a few weeks.”But because SARS-CoV-2 needs to large non-immune populations to speed up its mutation on a scale large enough to create a new variant, Dr Duchene said helping to vaccinate all corners of the globe as soon as possible may be able to halt further waves.Results of the Doherty research published in Molecular Biology and Evolution also show that an increased use of genetic sequencing of Covid infections in all nations is needed to detect the latest variants much more quickly than previously thought.In an exhaustive examination, the Doherty team traced the genetic changes of hundreds of genome sequences from SARS-CoV-2 strains to understand the mechanisms that resulted in new variants of concern.They discovered the mutations that resulted in the first four dangerous variants – Alpha, Beta, Gamma and Delta – occurred at a vastly accelerated evolutionary pace when given a chance to infect individuals for prolonged periods and then spread rapidly through unprotected populations.The acceleration was so strong that it took only six weeks for the mutations to take place resulting in the deadly Delta variant.“This shows that we need to address the evolution of the virus if we want to minimise the risk of variants appearing,” Dr Duchene said.“This is a good argument for better vaccine distribution worldwide.“It could be that somewhere around the world there is a variant emerging we haven’t seen because we have these surveillance blind spots where we just don’t know what is circling in some parts of the world.“Imagine if we detected Delta really early on you can just quarantine that and control it and it doesn’t spread around the world if we can detect it rapidly enough.”
Powered by WPeMatico
