The Omicron variant of coronavirus has been reported in 89 countries and the number of cases is doubling in 1.5 to 3 days in areas with community transmission, the World Health Organization (WHO) said on Saturday.
Omicron is spreading rapidly in countries with high levels of population immunity, but it is unclear if this is due to the variant’s ability to evade immunity, its inherent increased transmissibility or a combination of both, the WHO said in an update.
“There is consistent evidence that Omicron has a substantial growth advantage over Delta. It is spreading significantly faster than the Delta variant in countries with documented community transmission, with a doubling time between 1.5–3 days,” said WHO’s technical brief to member-countries. The saving grace so far has been Omicron’s lower virulence even though its spread underlines the need for measures like masks, sanitisation and avoidance of large gatherings along with vaccination.
The WHO designated Omicron, or B.1.1.529 variant, as a variant of concern (VOC) on November 26 after it was first detected in South Africa.
There is still limited data on the clinical severity of Omicron. More data are needed to understand the severity profile and how severity is impacted by vaccination and pre-existing immunity, the WHO said.
The overall threat posed by Omicron largely depends on how transmissible the variant is; how well vaccines and prior infection protect against infection, transmission, clinical disease and death; how virulent the variant is compared to other variants; and how populations understand these dynamics, perceive risk and follow control measures, including public health and social measures, it said.
There is still limited available data, and no peer-reviewed evidence, on vaccine efficacy or effectiveness to date for Omicron, the WHO added.
