Investigators, who analysed virus genomes from over 7,500 infected people, find nearly 200 mutations in the SARS-CoV-2 virus since China's outbreak but say this does not mean it is getting deadlier.
Scientists have found the coronavirus that causes Covid-19 has been in circulation since possibly October last year, evolving ever since it struck China with close to 200 "recurrent genetic mutations" in the virus.
The study "Emergence of genomic diversity and recurrent mutations in SARS-CoV-2" was carried out by a group of international scientists led by University College London.
The SARS-CoV-2 virus, which causes coronavirus disease or Covid-19, has infected more than 3.7 million, killed about 259,406 people and has devastated economic activities globally.
The study, led by the UCL Genetics Institute, analysed how the virus is adapting to humans and how that information can inform drug and vaccine design.
The team analysed virus genomes, using published sequences from over 7,500 people with Covid-19.
Genomes of 7,500 infected people studied
Scientists analysed virus genomes to understand how the virus mutated since it hit China's Wuhan city and engulfed almost the entire world, and if the exercise could offer "clues to direct drugs and vaccine targets."
The study said 198 sites in the SARS-CoV-2 genome appear to have already undergone recurrent, independent mutations "based on a large-scale analysis of public genome assemblies."
The study stipulates these recent recurrent mutations indicate the virus is still adapting to humans.
One of the lead authors, however, cautions a careful interpretation of the mutations.
"The virus is changing, but this in itself does not mean it's getting worse," Francois Balloux said to CNN.
He pointed out in another interview that all viruses mutate and there is nothing to suggest SARS-CoV-2's mutations are worrying or that it has become more deadly.
As early as October
“Our results are in line with previous estimates and point to all sequences sharing a common ancestor towards the end of 2019, supporting this as the period when SARS-CoV-2 jumped into its human host,” said the paper.
The analysis roughly supports the current understanding in the scientific community, that the pandemic started around November or December.
The paper places the jump of the virus into humans sometime around October 6, 2019 to December 11, 2019.
'Drugs and vaccines should focus on stable virus elements'
A key challenge to defeating coronavirus is if the virus has mutated, a drug might no longer be effective.
"If we focus our efforts on parts of the virus that are less likely to mutate, we have a better chance of developing drugs that will be effective in the long run," Balloux explained.
"We need to develop drugs and vaccines that cannot be easily evaded by the virus."