The Omicron coronavirus variant has been reported in 89 countries, and the number of cases in areas with community transmission is doubling every 1.5 to 3 days, according to the World Health Organization (WHO) on Saturday.
The WHO said in an update that Omicron is spreading rapidly in countries with high levels of population immunity, but it is unclear whether this is due to the virus’s ability to evade immunity, its inherent increased transmissibility, or a combination of both.
Omicron was designated a variant of concern by the CDC on Nov. 26, shortly after it was discovered, and much remains unknown about it, including the severity of the illness it causes.
“There are still limited data on the clinical severity of Omicron,” the WHO said. “More data are needed to understand the severity profile and how severity is impacted by vaccination and pre-existing immunity.”
“There are still limited available data, and no peer-reviewed evidence, on vaccine efficacy or effectiveness for Omicron to date,” it added.
The WHO warned that with the number of cases increasing so quickly, hospitals may become overburdened in some areas.
“Hospitalizations in the UK and South Africa continue to rise, and given rapidly increasing case counts, it is possible that many healthcare systems may become quickly overwhelmed.”