There are at least six strains of the SARS-CoV-2 coronavirus, which causes Covid-19, according to a study by the University of Bologna (Unibo) in Italy.
The virus shows little variability across the various strains, so the mutations should not significantly hamper the efforts of scientists to develop a vaccine, said a report on the study published on the Unibo website on August 3.
The full study has been published in the journal Frontiers in Microbiology under the title “Geographic and Genomic Distribution of SARS-CoV-2 Mutations.”
Researchers at Unibo drew from the analysis of 48,635 coronavirus genomes, which were isolated by researchers in labs all over the world. They then mapped the spread and the mutations of the virus during its journey to all continents.
The original that appeared in Wuhan, China in December 2019 is the L strain. The first mutation, called the S-strain, appeared at the beginning of 2020 and was followed by strains V and G in mid-January.
The G strain is currently the most widespread and mutated into the GR and GH strains at the end of February.
Across Europe and Italy, the most widespread is strain G, while the L strain from Wuhan is gradually disappearing
“The SARS-CoV-2 coronavirus is presumably already optimized to affect human beings, and this explains its low evolutionary change. This means that the treatments we are developing, including a vaccine, might be effective against all the virus strains,” said Federico Giorgi, researcher at Unibo and coordinator of the study.
Giorgi further said: “Strain G and its related strains GR and GH are by far the most widespread, representing 74% of all gene sequences we analysed.
“If we look at the coronavirus map, we can see that strains G and GR are the most frequent across Europe and Italy. According to the available data, GH strain seems close to non-existence in Italy, while it occurs more frequently in France and Germany. This seems to confirm the effectiveness of last months' containment methods,” he added.
In North America, the most widespread strain is GH, while in South America the GR strain is more common. In Asia, where the Wuhan L strain initially appeared, the spread of strains G, GH and GR is increasing.
The G, GH and GR strains landed in Asia only at the beginning of March, more than a month after their spread in Europe.
The novel coronavirus also has some less frequently occurring mutations that do not pose any risk at the moment, but should still be monitored, the researchers said.