Coronavirus mutations do not increase its transmissibility
The researchers found no evidence that any of the common mutations are increasing the virus’s transmissibility.
- Instead, they found some common mutations are neutral, but most are mildly detrimental to the virus.
- A new analysis of coronavirus genomes from over 15,000 Covid-19 patients from 75countries has found that none of the new mutations appears to be transmitted at a higher rate.
- The study, which is published today as a pre-print and has not yet been peer-reviewed, builds on another recent, peer-reviewed study published in the journal Infection, Genetics and Evolution.
- The previous study characterised patterns of diversity emerging in the genome of SARS-CoV-2.
- A novel technique to determine whether viruses with the new mutation are actually transmitted at a higher rate, and found that none of the candidate mutations appear to be benefiting the virus.
- Coronaviruses can develop mutations in three different ways: by mistake from copying errors during viral replication; through interactions with other viruses infecting the same cell; or as a result of the immune response of the host.
- Most mutations are neutral, while others are advantageous or detrimental to the virus.
- The researchers modelled the virus’s evolutionary tree, and analysed whether a particular mutation was becoming increasingly common within a given branch of the evolutionary tree.
- The researchers found no evidence that any of the common mutations are increasing the virus’s transmissibility. Instead, they found some common mutations are neutral, but most are mildly detrimental to the virus.
- The researchers found most of the common mutations appear to have been induced by the human immune system, rather than being the result of the virus adapting to its novel human host.