How coronavirus movements take over

The more people who suffer from the virus, the more likely it is to develop, according to Theodora Hatziioannou, a Rockefeller University physiologist who is studying the new variants.

Since the spread of the pandemic, scientists using SARS-CoV-2 samples collected around the world have been cataloging these genetic mutations. This allowed them to build a family tree showing the growth of the virus.

Here are some of the milestones in the evolution of the virus that causes Covid-19 and how tweaks to its genetic code have led to the new, potentially more infectious strains that are making their way worldwide:

Definite bias

Early last year, scientists discovered a mutation in Europe that makes the virus more portable than the original versions found in China.

The mutation, called D614G, alters the shape of spike proteins on the surface of the virus, making it more effective at binding to and infecting cells.

Modifications with D614G modification quickly adopted earlier versions of the virus.

“By June, it had replaced the ancestral virus,” said Jeremy Luban, a University of Massachusetts School of Medicine pathologist who studied the strain. “Everywhere he went, he became a mainstream.”

Summertime distribution

A new variant, called 20E (EU1), was first discovered in Spain last summer.

Since then it has spread widely across Europe.

20E (EU1) does not appear to have mutations that make it more mobile than early changes. Instead, it may have been just in the right place at the right time – a European holiday destination at the height of summer. “It could be a summer trip, it could be because you got rid of all your restrictions or it could be because it’s more mobile, ”Said Emma Hodcroft, an epidemiologist at the University of Bern in Switzerland, who led a study into the variant.

The new variables

There are several new variations in their spike protein genes in the recently discovered variants in the UK and South Africa.

Scientists believe that a single movement of these different variables could help the virus attach to and enter cells. The recently discovered variant of Brazil shares a major spike protein movement with the South African one.

“What we are seeing is just what we expect to see. The surface proteins of the virus are under great pressure to change, ”said Sean Whelan, a physiologist at the University of Washington in St. Louis. Louis. “The virus really cares about multiplying … If it can get into the cells of the [host] and bypass that host’s immune system, it multiplies. Causing infection is a different matter. ”

Some scientists are concerned that the South African variant may be better at avoiding antibodies made in response to natural infections and vaccines.

Initial estimates show that the variant from the UK is 50% -70% more susceptible than earlier versions of the virus. And UK scientists recently said early data suggested it could be more lethal.

The changes found in the UK and South Africa have been the main types in countries where they were first discovered.

The variant from the UK was found in more than two dozen US states through the end of January.

The Centers for Disease Control and Prevention expected it to become a major domestic mainstream by mid to late March if steps are not taken to slow it down. The variables were first detected in South Africa and Brazil in the USA

It is difficult to quantify the extent of their distribution. Apart from the UK and Denmark, many countries with active outbreaks have not made a wide spread of the virus, Dr Hodcroft said.

“At the moment, almost the rest of the world is a blind spot.”

Additional sources: Nextstrain (phylogenetic trees); Emma Hodcroft, University of Bern

Write to Daniela Hernandez at [email protected]