Knowns and unknowns

The discovery of the new Omicron coronavirus variant in South Africa last week caused alarm and swift action from a number of countries, including travel restrictions. Here’s what you need to know about it:

How was this variant found?

Scientists discovered the new variant in samples that were collected in South Africa as infections in the country began to explode last week after holding steady at about 200 a day. New cases neared 2,500 on Thursday.

Why is it called Omicron?

The World Health Organization named the variant after a letter in the Greek alphabet, as it has with four previous “variants of concerns.” The new strain is the first to be labeled a “variant of concern” since the Delta variant emerged in India in late 2020.

Why is Omicron a cause for concern?

The seemingly high number of mutations — about 30 — in the coronavirus’ spike protein could mean its spreads easily. That is about double the number of mutations of the Delta variant and could mean increased transmissibility. But the significance of the mutations is still not known, according to Sharon Peacock, who has led genetic sequencing of COVID-19 in Britain.

Does the Omicron variant make you sicker?

There’s no indication the variant will cause a more severe illness. The WHO said there was “preliminary evidence” to suggest an increased risk of reinfection with Omicron for those who have already had the virus as compared with other variants. No unusual symptoms have been reported with this variant, which can also lead to asymptomatic cases, according to South African health officials.

Will existing COVID-19 vaccines work against the variant?

Scientists say that it’s too soon to tell and that it will take a few weeks before they know. One expert, Peter Openshaw, a professor of experimental medicine at Imperial College London, called it “extremely unlikely” that current vaccines wouldn’t work against Omicron, noting they are effective against numerous other variants.