Professor Andrew Pollard revealed his “optimism” that current vaccines will continue to prevent serious disease – and suggested Omicron will not outrun the dominant Delta variant in Europe.
Alarm over Omicron has seen the UK impose flight bans on countries across southern Africa, where it was discovered, and warnings that domestic restrictions may be need to be reimposed.
Prof Pollard, the director of the Oxford Vaccine Group, said it is “too early” to be certain whether the new variant will be able to evade current vaccinations, something unlikely to be known for 2-3 weeks.
But he said most of the mutations in Omicron are in the same parts of the spike protein as those in the other variants that have emerged.
“That tells you that, despite those mutations existing in other variants, the vaccines have continued to prevent serious disease as we’ve moved through Alpha, Beta, Gamma and Delta,” he said.
“At least from a speculative point of view we have some optimism that the vaccine should still work against a new variant for serious disease, but really we need to wait several weeks to have that confirmed.
“It’s extremely unlikely that a reboot of a pandemic in a vaccinated population like we saw last year is going to happen.”
Prof Pollard also reassured people that the process for developing a new vaccine – if needed – is “increasingly well oiled”.
“That is something that could be moved very rapidly,” he told BBC Radio 4’s Today programme.
He also cast doubt on whether Omicron would overtake the Delta variant in Europe which, unlike South Africa, has a highly-vaccinated population.
“Delta is already pretty good, it’s spreading like wildfire across Europe,” Prof Pollard said.
But Professor John Edmunds, a member of the Sage advisory group, called for the return of compulsory mask-wearing in crowded settings now, questioning why it was ever lifted.
“I think we need to prepare, we need to run through our options. And the government needs to be prepared to act fast,” he told Times Radio.
“And, unfortunately, the lessons that we’ve learned throughout this epidemic is you have to act harder than you’d like to, wider than you like to, and faster than you’d like to.”
On Friday the health Secretary Sajid Javid said the government’s ‘plan B – mask-wearing, vaccine passports and working from home – would not be introduced, but told MPs: “If we need to go further, we will.”
He spoke as the UK saw 50,091 daily Covid cases – the highest level in a month – and 160 further deaths and as scientists said it was highly likely that Omicron will come to the UK.