The Omicron variant of the coronavirus is spreading significantly faster than the Delta strain in areas with community transmission, with the number of cases doubling in 1.5 to 3 days, the World Health Organization (WHO) has said.
The Omicron coronavirus variant has been reported in 89 countries.
The highly mutated variant is spreading rapidly in countries with high levels of population immunity, the WHO said, but it is unclear if this is due to the virus's ability to evade immunity, its inherent increased transmissibility, or a combination of both.
Also watch: Omicron is probably in most countries, warns WHO chief
WHO termed Omicron as a variant of concern on November 26, soon after it was first detected by scientists in South Africa, and much is still not known about it, including the severity of the illness it causes.
Earlier on Tuesday, the World Health Organisation chief said that even if the variant did cause less severe disease, a large number of cases could overwhelm unprepared health systems.