Videographic illustrating how a virus mutates. Several coronavirus variants with the potential to be more transmissible have caused global concern over whether existing vaccines will still protect the world from a virus that is constantly mutating.
- A virus mutates when there's a change to its genome. The set of instructions that contains the information the virus needs to function. Mutation occurs when the virus replicates while inside a host, such as a human body.
During replication, the genome is copied. Sometimes there's a mistake in this copying process. Just where the mistakes occur on the genome determines the impact on the virus's ability to survive or continue to replicate. All viruses go through some form of mutation. Some viruses, like the flu and measles viruses, mutate faster than others. However, most mutations have no impact on the properties of the virus.
Mutation could make a virus weaker or it could lead to changes that encourage infection to spread. For example, if the proteins on the surface of the virus mutate in such a way as to trick or counter the immune system in some way, a virus can become very dangerous. Scientists have tracked multiple mutations of SARS-COV-2, the virus that causes COVID-19, since it appeared in China in late 2019.