What are mutations and why are they important?

Viruses, particularly RNA viruses such as coronaviruses, constantly evolve through mutations in their genome. Mutations in the Sars-CoV-2 virus have been observed worldwide since the beginning of the pandemic. While most mutations do not have a significant impact, some may give the virus certain characteristics such as a selective advantage over others through increased transmissibility, increased pathogenicity with more severe forms of disease or the ability to circumvent immunity previously acquired by an individual either by natural infection or vaccination. In such cases, they become a cause for concern and should be monitored carefully.