The World Health Organization (WHO) said Friday that regions with community spread of Omicron were seeing cases doubling at a rate of once every 1.5 to 3 days, a higher pace than previous variants. In a technical brief issued on Dec. 17, the health agency said that Omicron has been detected in 89 countries so far, with “consistent evidence” that it has a substantial growth advantage over the Delta variant and warning that the rapid spread of the new mutation threatens to overwhelm many healthcare systems “quickly.” Omicron has as many as 32 mutations in its spike protein, some of which the WHO described as “concerning” as they may be able to evade human immune response, potentially making it more transmissible. “It is spreading significantly faster than the Delta variant in countries with documented community transmission, with a doubling time between 1.5–3 days,” the WHO said, adding that “it remains …