Mutations are a natural phenomenon when viruses replicate. Generally, RNA viruses have a higher rate of mutations compared with DNA viruses. However, unlike other RNA viruses, coronaviruses have fewer mutations. This is because coronaviruses have a genetic “proofreading mechanism” that corrects some of the errors made during replication. This is applicable to SARS-CoV-2 viruses too. As a result, SARS-CoV-2 viruses have “higher fidelity in its transcription and replication process than that of other single-stranded RNA viruses” says a February 2021 paper in Nature.
Providing fitness
The fate of new mutations depends on whether such mutations increase the fitness of the virus such as increasing the infectiousness of the virus and in light of many people being infected and/or vaccinated, the ability of the mutations to allow the virus to escape from immunity. Such mutations that provide increased fitness to the virus increase in numbers and become the dominant strain or variant.
