More than half of the Omicron patients in England were double jabbed, health officials have said, as the number of cases detected in the UK continues to rise sharply.
There were 75 further cases of the Covid-19 Omicron variant identified in England, the UK Health Security Agency (UKHSA) said on Friday night, report The Guardian.
It brings the total number of confirmed cases in England to 104 with 134 in the UK as a whole. There were warnings of a "small amount" of community transmission as not all the new cases were linked to travel.
On Friday, 16 cases were found in Scotland in the previous 24 hours, five times the increase recorded the previous day, with some linked to a Steps concert in Glasgow 11 days ago. Wales also announced its first case on Friday.
The sharp rise in cases came as a new risk assessment from the UKHSA said the new variant is "transmitting rapidly and successfully". A separate analysis by the agency of the first 22 Omicron cases in England also found that more than half of those infected had been double jabbed.
Twelve of the 22 cases occurred more than 14 days after the individual had received at least two doses of vaccine. Two cases were more than 28 days after a first dose of vaccine. Six were unvaccinated, while two had no available data.
None of the cases is known to have been hospitalised or died, but the UKHSA said that "most of the cases have a specimen date that is very recent and that there is a lag between onset of infection and hospitalisation and death."
The UKHSA has also issued its highest "red" alert against the virus for its theoretical ability, based on its mutations, to evade both vaccine and naturally acquired immunity. It also warns it could reduce the effectiveness of monoclonal antibody treatments.
However, the UKHSA's confidence level for the warnings is "low" as officials still lack key definitive data on the new variant.
Dr Jenny Harries, chief executive of the UKHSA, said: "Thanks to very high levels of vaccine coverage we already have a robust wall of defence against Covid-19 as new variants emerge.
"We are working as fast as possible to gather more evidence about any impact the new variant may have on severity of disease or vaccine effectiveness. Until we have this evidence, we must exercise the highest level of caution in drawing conclusions about any significant risks to people's health."
She added: "We have started to see cases where there are no links to travel, suggesting that we have a small amount of community transmission."