Should we worry about covid-19 mutations?
two different stories are presented here.
On 22 November, UK scientists revealed that they were monitoring 4,000 mutations of Covid-19, with some concern that the new strains may resist vaccines.
Are mutated viruses more dangerous?
Mutations don’t tend to add any changes that will lead to a virus being more harmful. However, the changes within the virus may affect how easily it is transmitted from person to person, which is why new strains of Covid-19 are often dubbed ‘more infectious.’
Dr Pitt explains, “When the virus is inside you, the factors of what lead you to become seriously ill are the same, regardless if it's a mutant form or not.
“This isn’t to say that there isn’t the capability of a new dangerous mutation appearing, but there is no evidence so far that any of the mutations are more harmful in creating a worse illness.”
2. None of the SARS-CoV-2 Genetic Mutations Appear to Increase Transmissibility
None of the mutations currently documented in the SARS-CoV-2 virus appear to increase its transmissibility in humans, according to a study led by University College London researchers.
The analysis of virus genomes from over 46,000 people with COVID-19 from 99 countries is published today (November 25, 2020) in Nature Communications.
First and corresponding author Dr. Lucy van Dorp (UCL Genetics Institute) said: “The number of SARS-CoV-2 genomes being generated for scientific research is staggering. We realized early on in the pandemic that we needed new approaches to analyze enormous amounts of data in close to real time to flag new mutations in the virus that could affect its transmission or symptom severity.
“Fortunately, we found that none of these mutations are making COVID-19 spread more rapidly, but we need to remain vigilant and continue monitoring new mutations, particularly as vaccines get rolled out.”
Coronaviruses like SARS-CoV-2 are a type of RNA virus, which can all develop mutations in three different ways: by mistake from copying errors during viral replication, through interactions with other viruses infecting the same cell (recombination or reassortment), or they can be induced by host RNA modification systems which are part of host immunity (e.g. a person’s own immune system).
Most mutations are neutral, while others can be advantageous or detrimental to the virus. Both neutral and advantageous mutations can become more common as they get passed down to descendant viruses.
The research team from UCL, Cirad and the Université de la Réunion, and the University of Oxford, analyzed a global dataset of virus genomes from 46,723 people with COVID-19, collected up until the end of July 2020.
The researchers have so far identified 12,706 mutations in SARS-CoV-2, the virus causing COVID-19. For 398 of the mutations, there is strong evidence that they have occurred repeatedly and independently. Of those, the researchers honed in on 185 mutations which have occurred at least three times independently during the course of the pandemic.
To test if the mutations increase transmission of the virus, the researchers modeled the virus’s evolutionary tree, and analyzed whether a particular mutation was becoming increasingly common within a given branch of the evolutionary tree — that is, testing whether, after a mutation first develops in a virus, descendants of that virus outperform closely-related SARS-CoV-2 viruses without that particular mutation.
The researchers found no evidence that any of the common mutations are increasing the virus’s transmissibility. Instead, they found most common mutations are neutral for the virus.
