The World Health Organization on Friday declared the recently discovered B.1.1.529 strain of COVID-19 to be a variant of concern, renaming it Omicron.
“Based on the evidence presented indicative of a detrimental change in COVID-19 epidemiology… the WHO has designated B.1.1.529 as a variant of concern, named Omicron,” the UN health agency said in a statement.
The WHO classified the strain as a highly transmissible virus of concern, the same category that includes the Delta variant, the world’s most prevalent. The panel said early evidence suggests an increased risk of reinfection.
Health experts have said the strain is the most concerning since Delta. Omicron, like Delta before it, is a letter in the Greek alphabet.
The announcement Friday from the United Nations health agency marks the first time in months that WHO has classified a COVID-19 variant as a variant of concern.
The discovery of the new variant sent a chill through much of the world Friday as nations raced to halt air travel, markets fell sharply and scientists held emergency meetings to weigh the exact risks, which were largely unknown.
Medical experts, including the World Health Organization, warned against any overreaction before the variant that originated in southern Africa was better understood. But a jittery world feared the worst nearly two years after COVID-19 emerged and triggered a pandemic that has killed more than 5 million people around the globe.
“We must move quickly and at the earliest possible moment,” British Health Secretary Sajid Javid told lawmakers.
There was no immediate indication whether the variant was more transmissible or causes more severe disease. As with other variants, some infected people display no symptoms, South African experts said.
Even though some of the genetic changes appear worrisome, it was unclear if the new variant would pose a significant public health threat. Some previous variants, like the beta variant, initially concerned scientists but did not spread very far.
The 27-nation European Union imposed a temporary ban on air travel from southern Africa, and stocks tumbled in Asia, Europe and the United States. The Dow Jones Industrial Average dropped more than 1,000 points. The S&P 500 index was down 2.3%, on pace for its worst day since February. The price of oil plunged nearly 12%.
“The last thing we need is to bring in a new variant that will cause even more problems,” German Health Minister Jens Spahn said. The member nations of the EU have experienced a massive spike in cases recently.
EU Commission President Ursula von der Leyen said flights will have to “be suspended until we have a clear understanding about the danger posed by this new variant, and travelers returning from this region should respect strict quarantine rules.”