A gene variant is a permanent change in the DNA sequence that makes up a gene. This type of genetic change used to be known as a gene mutation, but because changes in DNA do not always cause disease, it is thought that gene variant is a more accurate term.

Some variations are repaired by the cell’s DNA error correction mechanisms. Other variations are not and can be passed on to subsequently replicated cells; in such cases, the variation is termed a mutation. However, offspring can inherit the mutation only if germ cells are affected.

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.

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.