The UK has raised its COVID alert level due to the “rapid increase” in cases of the Omicron variant, the country’s four chief medical officers have said.
The advisers said on Sunday the public health risk assessment would move from level three to four – the second-highest level – which indicates “transmission is high and pressure on healthcare services is widespread and substantial or rising”.
Prime Minister Boris Johnson, under pressure because of claims he and staff flouted COVID-19 restrictions last Christmas, was due to make an address to the nation in the evening.
He was expected to talk about the country’s booster programme.
The decision to increase the five-stage public health risk assessment from level three to four came after a further 1,239 confirmed cases of the variant were recorded on Sunday.
That brought the total number of UK cases of Omicron to 3,137 – a 65 percent increase from Saturday’s total of 1,898.
The UK began easing coronavirus restrictions in June and the alert level was at stage three, which means the pandemic is in general circulation.
The four chief medical officers for England, Wales, Scotland and Northern Ireland said the move was prompted by advice from the UK Health Security Agency, a public health body.
“Transmission of COVID-19 is already high in the community, mainly still driven by Delta, but the emergence of Omicron adds additional and rapidly increasing risk to the public and healthcare services,” they said in a joint statement.
“Early evidence shows that Omicron is spreading much faster than Delta and that vaccine protection against symptomatic disease from Omicron is reduced.
“Data on severity will become clearer over the coming weeks but hospitalisations from Omicron are already occurring and these are likely to increase rapidly.”
The World Health Organization also said on Sunday that Omicron was more transmissible than the Delta strain and reduced vaccine efficacy but caused less severe symptoms according to early data.
The UK officers said boosters were vital given that vaccine protection was reduced with Omicron, and both third jabs used – Pfizer and Moderna – increased immune response and showed “good effectiveness”.
The move was designed to reduce already increased pressure on the state-run National Health Service (NHS) which is dealing with seasonal respiratory infections such as flu.
The government earlier announced additional measures to stop the spread of Omicron after facemasks were made compulsory in many indoor public places last Friday.
From Tuesday, fully vaccinated contacts of people who test positive for COVID will be required to take daily lateral flow tests for seven days.
But those who have not had one or two shots of a COVID vaccine will have to self-isolate for 10 days, the Department of Health and Social Care said.
“The Omicron variant is quickly gaining ground in the UK and is expected to become the dominant strain by mid-December,” said Health Secretary Sajid Javid.
“We are taking this proportionate and more practical measure to limit the impact on people’s day-to-day lives while helping to reduce the spread of Omicron.”
The government has set itself a target of giving everyone aged 18 and over a booster jab by the end of January and has opened up the programme to the over-30s from Tuesday.
The announcement adds to proposals from Johnson to combat Omicron, including a return to home-working if possible from Monday, and the introduction of vaccine passports in certain settings from Wednesday.
Parliament will vote to make the proposals law on Tuesday, with Johnson facing a potentially sizeable rebellion from his own Conservative colleagues.
The vote, though, is likely to pass with Labour support.
The UK – one of the worst-hit countries by COVID-19 with more than 146,000 deaths – began its mass vaccination campaign just more than a year ago.
Infection rates remain stubbornly high at about 50,000 positive tests a day. In London, Omicron accounts for about a third of all COVID-19 cases.
The Delta variant, first identified in India earlier this year, is currently responsible for most of the world’s coronavirus infections.
South Africa’s discovery of Omicron – which has a large number of mutations – last month prompted countries around the world to impose travel bans on southern African countries and reintroduce domestic restrictions to slow its spread.
The WHO said Omicron had spread to 63 countries as of December 9. Faster transmission was noted in South Africa, where Delta is less prevalent, and in the UK, where Delta is the dominant strain.