The PM’s comments come as eight further cases of the variant have been confirmed in England, bringing the total number in the country to 13. Cases of Omicron have now reached 22 across the UK.
Earlier in the day, Dr Jenny Harries, chief executive of the UK Health Security Agency, urged people not to socialise if they do not need to in the run-up to Christmas, and Johnson was asked at a Downing Street press conference if festive parties should be cancelled.
He replied: “So the answer is no. The guidance remains the same, and we’re trying to take a balanced and proportionate approach.
“We’ve got the measures in place to fight Delta, which we think are appropriate, and then we’re bringing in some tougher measures to stop the rapid seeding of Omicron in this country to give us the time we need to get the boosters in and of course to find out more.”
Asked whether parties and Nativity plays should be scrapped, Johnson said: “We don’t want people to cancel such events and we think that, overwhelmingly, the best thing for kids is to be at school, as I have said many times throughout this pandemic.
“What we are doing is trying to take a balanced and proportionate approach to the particular risk that seems to be posed by Omicron – certainly is posed by Omicron – focused in particular on measures at the border.”
He described the new measures as “the right balance”. The UK’s response has included stricter travel measures, insisting on increased mask use and expanding the booster vaccination programme.
It is the booster campaign which the government believes provides the greatest line of defence against Omicron and Johnson used a Downing Street press conference to promise another “great British vaccination effort” to deliver millions of jabs.
“We’re going to be throwing everything at it, in order to ensure that everyone eligible is offered that booster in just over two months,” he said.
Health secretary Sajid Javid said the booster programme would be put “on steroids” to meet the target, while NHS England’s chief executive Amanda Pritchard said staff are working at “breakneck speed”.
Harries’ comments caused alarm in the hospitality industry and helped fuel a Tory backbench revolt which saw Conservatives rebel over restrictions which came into force in England on Tuesday morning to tackle Omicron.
She told BBC Radio 4’s Today programme that even if our “vaccines appear to be effective, but we find that the variant is more highly transmissible, having lowish grade infection, but in very large numbers of the population, (it) could still be a significant impact on our hospitals.
“And, of course, our behaviours in winter and particularly around Christmas, we tend to socialise more, so I think all of those will need to be taken into account.”
Asked whether people should be told to work from home in England, as is happening in Scotland, Wales and Northern Ireland, she said: “We’ve seen that not everybody has gone back to work and I’d like to think of it more in a general way, which is if we all decrease our social contacts a little bit, actually that helps to keep the variant at bay.”
She suggested “being careful, not socialising when we don’t particularly need to” and getting a booster jab.
Kate Nicholls, chief executive of the UKHospitality trade body, said this “chilling talk” could hammer the sector ahead of its busiest period.
She said bookings have already been “cancelled and plans changed” by some customers.
Johnson rejected suggestions that advice on working from home should be reinstated in response to the concerns about Omicron, which scientists believe could be more transmissible than the dominant Delta variant and may render vaccines less effective because of the extent of its mutations.
Asked why that advice was not in place in England, Johnson said: “This is not something that we think currently is necessary.”