None of the mutations documented in the new coronavirus appears to make Covid-19 spread more rapidly, scientists have said.
However, they have warned the world needs to remain vigilant and continue monitoring the genetic changes in Sars-Cov-2, the virus that causes Covid-19.
This is because the imminent introduction of vaccines may "exert new selective pressures on the virus" that may lead to mutations that do not respond to jabs.
The findings, published in the journal, are based on coronavirus genomes, or genetic material, from more than 46,000 people with Covid-19 from 99 countries.
"The virus may well acquire vaccine-escape mutations in the future, but we're confident we'll be able to flag them up promptly, which would allow updating the vaccines in time if required," said lead author Professor Francois Balloux of University College London's Genetics Institute.
Mutations in coronaviruses can develop in three ways, said the researchers. These are mistakes resulting from copying errors as the virus replicates itself inside the human body, through interactions with other viruses infecting the same cell, and changes induced by the host's or a person's own immune system.
Scientists from University College London, along with experts from Cirad, the Universite de la Reunion, and the University of Oxford, analysed a global dataset of Sars-Cov-2 genomes from 46,723 people, collected until the end of July 2020.
The teams have so far identified 12,706 mutations in Sars-Cov-2.
The researchers said there was strong evidence that mutations have occurred repeatedly and independently in 398 of the cases.
Based on a modelling of the virus's evolutionary tree, the scientists said they 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. The researchers said 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.
However, they added this was in contrast to what happened when Sars-Cov-2 later jumped from humans into farmed minks.
The researchers said that while Sars-Cov-2 will eventually diverge into different lineages as it becomes more common in human populations, it does not necessarily mean these lineages will be more transmissible or harmful.