The World Health Organization's technical advisory group said Friday it has assigned the B.1.1.529 variant of the coronavirus that causes COVID-19 the Greek letter omicron and said it has been designated a "variant of concern." Earlier reports suggested the variant would be assigned the letter nu. The variant, which was first reported from South Africa, led the U.K. and European Union to implement travel bans on South Africa and neighboring countries on Friday, amid concerns it may be more transmissible than the original virus and more lethal. "This variant has a large number of mutations, some of which are concerning," the group said in a statement. "Preliminary evidence suggests an increased risk of reinfection with this variant, as compared to other VOCs. The number of cases of this variant appears to be increasing in almost all provinces in South Africa." For now, there are a number of studies underway, and the group will continue to monitor and track the variant. It called on countries to enhance surveillance and sequencing efforts, to submit complete genome sequences and associated metadata to a publicly available database and to report cases and clusters to the WHO. "Individuals are reminded to take measures to reduce their risk of COVID-19, including proven public health and social measures such as wearing well-fitting masks, hand hygiene, physical distancing, improving ventilation of indoor spaces, avoiding crowded spaces, and getting vaccinated," said the statement.