The world reacted with alarm Friday to the highly mutated new coronavirus variant discovered in southern Africa, as the United States, the European Union and nations across the globe imposed new travel restrictions, financial markets swooned, and visions of finally emerging from the pandemic started to dim.
Just two days after the world learned of the variant, the World Health Organization officially labeled it a “variant of concern,” its most serious category — the first since the delta variant, which emerged a year ago. The designation means that the variant has mutations that might make it more contagious or more virulent, or make vaccines and other preventive measures less effective — although none of those effects has yet been established.
After an emergency meeting, WHO warned in a statement that “preliminary evidence suggests an increased risk of reinfection with this variant” in people who have already had COVID-19. WHO dubbed the new variant omicron.
WHO and scientists on multiple continents cautioned that very little is known about the omicron variant or about whether the dangers it poses will justify the fears it is stoking. South African scientists announced its existence Wednesday, and the number of cases definitively identified, all of them within the past three weeks, is still small — under 100.
On Friday, Israel, Singapore, several European nations individually, and then the European Union as a whole, the United States and Canada followed the lead set by Britain on Thursday night, temporarily barring foreign travelers who have recently been in South Africa or any of several neighboring countries. As with past travel bans, countries are allowing their own citizens and permanent residents to return home if they test negative for the virus, with some requiring additional testing and quarantine after arrival.
After a briefing by his top advisers on the pandemic, including Dr. Anthony Fauci, President Joe Biden made the decision to bar travelers from South Africa, Botswana, Zimbabwe, Namibia, Lesotho, Eswatini, Mozambique and Malawi starting Monday.
“It’s going to buy us some time,” Fauci said in an interview. “It’s not going to be possible to keep this infection out of the country. The question is: Can you slow it down?”
This article originally appeared in The New York Times.