What do we know about the new coronavirus strains?

Multiple variants of SARS-CoV-2, the scientific name for coronavirus, have emerged in the past two months causing global concern about the course of the outbreak.

While not much information is available on these strains so far, scientists are trying to find out whether these new variants could undermine current coronavirus vaccines, or cause more severe disease.

The new mutations triggered alarm as they continue to circulate around the globe. Here we explain how the virus mutates and what we should expect next.

How did it start?

It was first detected in the UK in November. Since then, it has been reported in many countries such as Israel, Denmark, Belgium, the Netherlands, Jordan, Italy, South Africa and Australia. 

American officials confirmed on Tuesday the first case of a new strain of Covid-19 in the United States, which was caused by a contagious UK variant and could be as much as 70 percent more transmissible. 

Experts state that new strains of the coronavirus have been detected nearly since its first appearance in China around a year ago.

However, it got global traction after it was first reported in the UK last month, becoming widespread in the southeast region, reportedly accounting for 60% of recent infections in London.

What is the UK variant?

"We do not know why this variant has emerged in the UK,” said the Centers for Disease Control and Prevention, CDC, “by chance alone, viral variants often emerge or disappear… alternatively, it may be emerging because it is better fit to spread in humans.”

Viruses evolve naturally as they circulate through the population. That is the reason why a new flu vaccine developed each year. They often acquire minor changes of a letter or two in their genetic alphabet just through normal evolution. 

Scientists name the coronaviruses after the crown-like spikes on their surfaces. The mutations cause a change in protein building blocks and deletions. There are many thousands of lineages of coronavirus which differ on average by only a small number of defining mutations.

 The UK variant is referred to as “SARS-CoV-2 VOC 202012/01”, or “B.1.1.7.”. It has a mutation in the receptor-binding domain of the spike protein. 

The variants detected so far

The CDC said several new variants emerged in the fall of 2020, the most notables are listed in the UK, South Africa and Nigeria.

In contrast to the UK variant, the South African variant, a.k.a. 501Y.V2, or B.1.351, does not contain the specific deletion. It was first identified in Nelson Mandela Bay, South Africa, according to the CDC. 

Another variant is called B.1.207, from Nigeria. African scientists identified two coronavirus sequences that share one non-synonymous mutation in the spike protein in common with the UK variant.

The latter is associated with increased transmissibility, while the other two are still researched. There is no evidence yet to indicate that these variants have any impact on disease severity or vaccine efficacy.

The researchers in Sweden also found in April a virus with two genetic changes that seemed to make it roughly two times more infectious.

Can the variants undermine vaccines?

 Experts note that vaccines produce various responses by the immune system beyond just those to the spike protein.

Speaking to Anadolu Agency, BioNTech's CEO and co-founder Ugur Sahin said last week that he did not see any problem with the effectiveness of their vaccine against mutations.

“This is not the first time the virus mutates. There were several mutations before. We checked all the mutations in the past and we don’t see any problem… there is no such thing that the vaccine is not going to be effective,” he said.

Moderna, CureVac and AstraZeneca also believe their shots will work against the new threat.

Both the Moderna and the Pfizer/BioNTech vaccines have shown 95 percent efficacy rates in their clinical trials against the virus. Their success against the variants is still unclear.

Sahin said the vaccine contains more than 1,270 amino acids, and only nine of them are changed in the mutated virus, which means that 99% of the protein is still the same.