Early evidence suggests Covid-19 vaccines may be less effective against Omicron - and that the variant has a higher risk of reinfection, the World Health Organisation says.
In its latest weekly update on Wednesday, the WHO said current data indicates Omicron has a transmission advantage over Delta.
It said that more data were needed to understand the extent to which Omicron can evade immunity from vaccines or previous infection.
“Preliminary evidence suggests that there may be a reduction in vaccine efficacy and effectiveness against infection and transmission associated with Omicron, as well as an increased risk of reinfection,” the WHO said.
As of December 14, Omicron had been confirmed in 76 countries, it said.
Its briefing added: “Based on current limited evidence Omicron appears to have a growth advantage over Delta.
“It is spreading faster than the Delta variant in South Africa where Delta circulation was low, but also appears to be spreading more quickly than the Delta variant in countries where the incidence of Delta is high, such as in the United Kingdom.”
The overall picture is that the “risk related to the new variant of concern Omicron remains very high," it said.
However, more positively, it said that the efficacy of routine testing methods do not appear to be affected by the new variant, and that treatments to help patients with severe Covid also remained effective.
The UK is braced for a “tidal wave” of the new variant, with internal Government modelling predicting that hundreds of thousands of people could be becoming infected daily.
The chief executive of the UK Health Security Agency, Dr Jenny Harries, said Wednesday that Omicron was “probably the most significant threat we’ve had since the start of the pandemic”.
Meanwhile public health expert Professor Tim Spector said that cases in London were rising at their sharpest rate since the first wave.
