A genetic study of samples from more than 7,500 COVID-19 infected people suggests that the new coronavirus spread quickly around the world after it appeared in China sometime between October and December last year, scientists said Wednesday.
Scientists at University College London’s Genetics Institute found nearly 200 recurring genetic mutations of the new coronavirus – SARS-CoV-2 – that UCL researchers said showed how it adapts to its human hosts as it spreads.
“Phylogenetic estimates support that the COVID-2 pandemic started sometime around October 6, 2019 to December 11, 2019, which corresponds to the time of the host’s jump on humans,” wrote the research team, led by Francois Balloux. in a study published in the journal Infection, Genetics and Evolution.
Balloux said the analysis also found that the virus mutated and is, as is normally the case with viruses, and that much of the global genetic diversity of the virus causing COVID-19 was found in all of the hardest-hit countries.
That suggests that SARS-CoV-2 was widely transmitted around the world from the outset of the epidemic, he said.
“All viruses naturally mutate. Mutations in themselves are not a bad thing and there is nothing to indicate that SARS-CoV-2 mutates faster or slower than expected, ”he said. “So far, we cannot say whether SARS-CoV-2 becomes more or less deadly and contagious.”
In a second study also published Wednesday, scientists from the British University of Glasgow who also analyzed SARS-CoV-2 virus samples said their findings showed that previous research suggesting that there were two different strains was inaccurate.
ONLY A CIRCULATING VIRUS TYPE
An initial study by Chinese scientists in March had suggested that there may have been two strains of the new coronavirus causing infections there, more of which were “more aggressive” than the others
But when they published their analysis in the journal Virus Evolution, the Glasgow team said there was only one type of virus in circulation.
According to a Reuters report, more than 3.71 million people worldwide are infected with the new coronavirus and 258,186 people have died.
Cases have been reported in more than 210 countries and territories since they were first identified in China in December 2019.
The genetic studies provide “fascinating” insights into the evolution of the virus and emphasize that it is “a moving target with an unknown evolutionary destination,” said Jonathan Stoye, head of the virology department at the British Francis Crick Institute.
“All of the evidence is completely consistent with an origin late last year, and there is no reason to question it in any way,” said Stoye.
A study by French scientists published earlier this week found that a man in France was infected with COVID-19 as early as December 27, nearly a month before authorities confirmed the first cases there.
The World Health Organization said the French case was “not surprising” and urged countries to investigate other early suspected cases.
Balloux’s team examined the genomes of more than 7,500 viruses from infected patients around the world. Their results add to a growing body of evidence that SARS-CoV-2 viruses have a common ancestor as of late 2019, suggesting that this was when the virus from a previous animal host sprang on humans.
The UCL researchers also found nearly 200 small genetic changes or mutations in the coronavirus genomes they analyzed – findings that Balloux said provided useful clues for researchers seeking to develop drugs and vaccines.