LONDON, UK — This week, scientists in South Africa identified a new coronavirus variant that they say is responsible for a recent increase in COVID-19 infections in Gauteng, the country's most populous province.

It's unclear where the new variety originated, but scientists in South Africa discovered it initially, and it's already been found in travellers from Belgium, Botswana, Hong Kong, and Israel.

Health Minister Joe Phaahla said the variant was connected to a "exponential surge" in instances in recent days, however specialists are still unsure if the new variant, known as B.1.1.529, is actually responsible. 

From slightly over 200 new confirmed cases each day in recent weeks, the number of new cases per day in South Africa increased to 2,465 on Thursday. Scientists investigated virus samples from the outbreak and discovered the new type while trying to figure out why there was such a dramatic increase in cases.

The World Health Organization categorised it as a "variant of concern" in a statement released on Friday, designating it "omicron" after a Greek letter.

The United Nations' health agency warned that "preliminary evidence implies an increased risk of reinfection with this variant," compared to other variants, after assembling a committee of specialists to examine the data.

The WHO stated, "The number of cases of this variety appears to be increasing in practically all provinces in South Africa."

Why are scientists worried about omicron?

The coronavirus' spike protein appears to have a significant number of mutations — roughly 30 — which could alter how easy it spreads to people.

The data thus far suggest the novel variation has alterations "associated with improved transmissibility," but "the significance of many of the mutations is yet unknown," according to Sharon Peacock, who conducted the genetic sequencing of COVID-19 in Britain at the University of Cambridge.

The variant is "the most heavily mutated version of the virus we have encountered," according to Lawrence Young, a virologist at the University of Warwick. "It appears like it's spreading rapidly," he said, despite the fact that the mutation was only discovered in low levels in portions of South Africa.

Dr. Anthony Fauci, the top infectious diseases expert in the United States, said American officials had scheduled a call with their South African counterparts for later Friday to learn more specifics, and that there was no indication the variant had arrived in the United States yet.

What is known about omicron and what is unknown?

Scientists know the new version differs genetically from prior variants like as the beta and delta variants, but they don't know if these differences make it more transmissible or harmful. There is currently no evidence that the variation causes more severe illness.

It will probably take weeks to figure out if the new variation is more contagious and if vaccines against it are still effective.

Even if some of the new variant's genetic changes appear to be concerning, it's yet unknown whether they will represent a public health risk. Previous varieties, such as the beta version, concerned scientists at first but did not spread very far.

"We don't know if this new variation will gain a foothold in delta-dominated regions," Peacock of the University of Cambridge remarked. "Where there are other varieties circulating, the jury is yet out on how well this version will do." Delta is currently the most common COVID-19 variant, accounting for more than 99 percent of sequences submitted to the world's largest public database.

How did this new variant arise?

As the coronavirus spreads, it mutates, and many new varieties, including ones with potentially dangerous genetic modifications, die off. Scientists are hunting for alterations in COVID-19 sequences that could make the disease more transmissible or lethal, but they can't tell just by looking at the virus.

The variant "may have evolved in someone who was infected but couldn't clear the virus, allowing the virus to genetically evolve," according to Peacock, in a scenario similar to how experts believe the alpha variant — which was first identified in England — emerged, by mutating in an immune-compromised person.

Are the travel restrictions being imposed by some countries justified?

Maybe.

The United States joined the European Union and a number of other countries in imposing travel restrictions on visitors from southern Africa on Friday.

Beginning Monday, the United States will restrict travel from South Africa and seven other countries in the area, according to the White House. It did not go into detail, except to note that the limits will not apply to returning citizens or permanent residents of the United States, who will continue to be needed to test negative before travelling.

Travelers travelling in the United Kingdom from South Africa, Namibia, Botswana, Lesotho, Eswatini, and Zimbabwe will be required to self-isolate for 10 days as of noon Friday. On Friday, European Union nations moved rapidly to try to halt plane flights from southern Africa.

Restricting travel from the region is "prudent" and would allow authorities more time given the recent rapid surge in COVID-19 in South Africa, according to Neil Ferguson, an infectious diseases expert at Imperial College London.

The early finding of the new variant, according to Jeffrey Barrett, head of COVID-19 Genetics at the Wellcome Sanger Institute, could mean that constraints put in place now have a greater impact than when the delta variant originally appeared.

"With delta, it took many, many weeks into India's dreadful wave before it became evident what was going on, and by that time, delta had already seeded itself in many areas throughout the world, and it was too late to do anything," he said. "With this new variety, we may be at an earlier stage, so there may still be time to do something about it."