Since the emergence of the new coronavirus, called SARS-CoV-2, several researchers have proposed that there is more than one strain.
Genetic mutations are a natural, everyday phenomenon. They can occur every time genetic material is copied.
When a virus replicates inside the cell it has infected, the myriad of new copies will have small differences. Why is this important?
When mutations lead to changes in how a virus behaves, it can have significant consequences. These do not necessarily have to be detrimental to the host, but in the case of vaccines or drugs that target specified viral proteins, mutations may weaken these interactions.
Since the emergence of SARS-CoV-2, several research studies have highlighted variations in the virus’s genetic sequence. This has prompted discussion about whether or not there are several strains, if this has an impact on how easily the virus can infect a host, and whether or not this affects how many more people are likely to die.
Many scientists have called for caution. In this Special Feature, we summarize what researchers currently know about SARS-CoV-2 mutations and hear from experts about their views on what these mean for the pandemic.
Why are mutations significant?
SARS-CoV-2 is an enveloped RNA virus, which means that its genetic material is encoded in single-stranded RNA. Inside a host cell, it makes its own replication machinery.
RNA viruses have exceptionally high mutations rates because their replications enzymes are prone to errors when making new virus copies.
Virologist Prof. Jonathan Stoye, a senior group leader at the Francis Crick Institute in London in the United Kingdom, told Medical News Today what makes virus mutations significant.
“A mutation is a change in a genetic sequence,” he said. “The fact of a mutational change is not of primary importance, but the functional consequences are.”
If a particular genetic alteration changes the target of a drug or antibody that acts against the virus, those viral particles with the mutation will outgrow the ones that do not have it.
“A change in a protein to allow virus entry into a cell that carries very low amounts of receptor protein could also provide a growth advantage for the virus,” Prof. Stoye added.
“However, it should be stressed that only a fraction [of] all mutations will be advantageous; most will be neutral or harmful to the virus and will not persist.”
“Mutations in viruses clearly do matter, as evidenced by the need to prepare new vaccines against [the] influenza virus every year for the effective prevention of seasonal flu and the need to treat HIV-1 simultaneously with several drugs to [prevent the] emergence of resistant virus.”
– Prof. Jonathan Stoye
Medical reference: Medical News Today