These errors in the viral RNA are called mutations, and viruses with these mutations are called variants. Variants could differ by a single or many mutations. Not all mutations have the same effect.

Any changes to the viral genetic sequence during this process is known as a mutation and viruses with new mutations are sometimes called variants. Variants can differ by one or multiple mutations.

The changes in the nucleotide sequence at the DNA level or in any one of the base pairs is known as mutation, while the genetic variation is how one individual of a species variate from another, variation can be due to changes in the nucleotide sequence like insertions, deletions, any genetic rearrangements or any environmental factors.

To recap, genetic variants are differences in your DNA that you are born with, while genetic mutations are changes that happen to DNA during your lifetime — both can cause cancer.