REFILE-FACTBOX-How the new coronavirus has evolved

(Fixed that Wuhan is a city, not a state.)

Sydney, December 10 (Reuters)-Coronavirus SARS-CoV-2 has swept the globe, killing more than 1.5 million people in the past year and adapting to humans, mutating into seven major groups or strains Did. host.

Mapping and understanding these changes to the virus is important for developing strategies for combating the COVID-19 disease caused by the virus.

“The reason we look at genomics is to figure out where it came from … that information is important in terms of revealing what to expect from a pandemic,” said South Australia’s Chief Health Officer. , Said Nicola Sprie. After the outbreak in the state in early November.

Reuters analyzes more than 185,000 genomic samples from the Global Initiative for Influenza Data Sharing (GISAID), the world’s largest novel coronavirus genome sequence database, and how the global dominance of major strains changes over time I showed you what you did.

The original strain detected in Wuhan, China in December 2019 is the L strain. The virus then mutated to the S strain in early 2020. This was followed by V and G shares. The G strain was further mutated into GR, GH, and GV strains. Several other rare mutations were grouped together as an O strain.

(Reuters graphics: tmsnrt.rs/3n9197O)

Mutation tracking

Mutations are changes in the genetic material of an organism. If a virus makes millions of copies of itself and moves from host to host, not all copies are the same. These small mutations accumulate as the virus spreads and are copied many times.

In the early days of the pandemic, the virus spread relatively rapidly around the world, was repeatedly introduced in various places, and caused regular new outbreaks. Meanwhile, some of the samples reported to GISAID contained a mixture of more diverse strains.

As countries began to close their borders, fewer new strains were introduced, and in countries with more elastic G-strains, they began to dominate.

In Asia, the original L stock lasted longer as several countries, including China, closed their borders and curtailed movement. In contrast, North America and Europe were less restrictive, at least initially, so the G strain spread and mutated at a faster pace.

“The virus travels at superspreading events, which means the virus doesn’t have to be particularly contagious,” said Catherine Bennett, epidemiology chairman at Deakin University’s School of Health in Melbourne. “Because of the cluster transmission, we can see various patterns.”

Currently, G stock is dominant all over the world. One particular mutation, D614G, has become the most common mutant.

The latest mutation to emerge is the GV strain, which has so far been isolated in Europe, and experts say whether this strain is spreading due to the benefits of infection, or socially active young adults and tourism. It is unclear if it affected the guests in the summer.

Why mutations are important

The SARS-CoV-2 virus has been slowly mutated so far, giving scientists and policy makers an eye on its progress.

Still, scientists are controversial about the effects of some mutations. Some experts report that the D614G variation increased the infectivity of the virus, but other studies contradict it.

In any case, the changes so far have not resulted in strains that appear to be resistant to the vaccine under development.

However, experts who have observed influenza and HIV mutating over the years avoiding the vaccine warn that future mutations in SARS-CoV-2 remain unknown. And the best way to avoid changes that make the virus impervious to the vaccine is to limit its spread and reduce the chances of having to mutate.

“If the virus, especially the spike protein, changes significantly, we may escape the vaccine. We want to slow down the transmission globally to slow down the clock,” said Deakin Bennett. “It reduces the possibility of one of the tens of millions of changes that is terrible news for us.”