How will variants change our response to COVID-19?
The growing outbreak of COVID-19 in Sydneys suburbs has cast a spotlight on the Delta variant of the SARS-CoV-2 virus. We are now on day 28 of the outbreak and already 864 cases have been reported, whereas during Victorias second wave this number was not reached until Day 38. This is despite NSW having better public health systems and control measures in place than Victoria did a year ago. This sums up the impact and seriousness of the increased infectiousness of Delta compared with the original Wuhan strain. A nurse fills syringes with Pfizer vaccines at a COVID-19 vaccination clinic. All viruses change over time, especially viruses that have a genome made of RNA rather than DNA. RNA genomes are often not copied as faithfully as DNA genomes, meaning as the virus replicates its genes undergo random copying errors (ie. genetic mutations). Over time, these errors can lead to alterations in various viral proteins. The process of natural selection then comes in to play, if the mutant virus has a survival advantage then it will outcompete its parent and before long this mutant, or new variant, will be the dominant virus detected.