Study Finds SARS-CoV-2 Has Six Strains

A study conducted by researchers at the University of Bologna shows that SARS-CoV-2, the virus causing the COVID-19 pandemic, presents at least six strains. Despite its mutations, the virus shows little variability, which is a good news welcomed by researchers working on a viable vaccine. The most extensive study ever carried out on SARS-CoV-2 sequencing drew from the analysis of 48,635 coronavirus genomes isolated by researchers from all over the world.

Currently, there are six strains of coronavirus. The original one is the L strain, that appeared in Wuhan, China in December 2019. Its first mutation, the S strain, appeared at the beginning of 2020. Since mid-January of 2020, strains V and G appeared. By end of February 2020, strain G — the most widespread — mutated into strains GR and GH.

According to the researchers, strain G and its related strains GR and GH are by far the most widespread, representing 74% of all gene sequences that they analyzed. The strains present four mutations, two of which are able to change the sequence of the RNA polymerase and Spike proteins of the virus. This characteristic probably facilitates the spread of the virus.

Strains G and GR are the most frequent across Europe and Italy. However, the GH strain is close to non-existence in Italy, while it occurs more frequently in France and Germany. In North America, the most widespread strain is GH, while in South America the GR strain is more frequent. In Asia, where the Wuhan L strain initially appeared, the spread of strains G, GH, and GR is increasing. These strains landed in Asia only at the beginning of March, more than a month after their spread in Europe. Globally, strains G, GH, and GR are constantly increasing. Strain S can be found in some restricted areas in the US and Spain. The L and V strains are gradually disappearing.

For more details, read the news article in the University of Bologna website.