By John Ely

You only need to be exposed to 'a whiff of infected breath' to catch Omicron, one of the Government's scientific advisers said today.

Professor Peter Openshaw, a member of the New and Emerging Respiratory Virus Threats Advisory Group - a sub-committee of SAGE, said: 'Omicron is so infectious.'

'It has ended up being so infectious that it almost needs just a whiff of infected breath and you could get infected.'

He added that the UK was lucky that the original strain of Covid, that emerged from Wuhan in early 2020, had not possessed Omicron's high transmissibility.

'We’re lucky really that it wasn’t this infectious when it first moved into human-to-human transmission,' he said.

While Omicron is known to be ultra-transmissible, mounting evidence shows it is triggering milder illness.

Scientists are still unclear whether this is due to the virus itself being less inherently deadly or because of the protection people now enjoy from getting a Covid shot or a prior infection of the virus.

But Professor Openshaw added that while the UK had a high vaccination rate against Covid, affording most people protection from severe disease from the virus, other nations were not as fortunate.

'We’re in a relatively good position in countries like the UK.'

'But I think you have to remember that in many parts of the world the vaccination rates are only about 5 per cent, and they’re being exposed to this very infectious virus with very little protection.'

His comments come as a record 189,213 coronavirus cases were logged across the UK yesterday.

While the number of hospital patients with Covid in England rose to 11,452, a rise of 61 per cent in just one week.

The rise in cases and therefore potential demands on the health service has prompted NHS bosses to warn that the Government 'needs to be ready to introduce tighter restrictions at real speed should they be needed'.

Chris Hopson, the head of NHS Providers, said new curbs 'may be needed at pace if the evidence warrants it' as he said health bosses 'still don't know' if there will be a surge in elderly hospitalisations which could trigger Mr Johnson to act.

Boris Johnson is expected to make a decision in the first week of the New Year on whether to restrict mixing indoors in England.

The Prime Minister opted not to impose new curbs between Christmas and New Year's Eve but rising Covid case numbers are fuelling fears that new measures could be on the horizon.

A key issue is number of NHS workers in England absent due to Covid, which has doubled in two weeks to nearly 28,000 per day.

Nearly 25,000 staff were ill with the virus or self-isolating on Boxing Day, more than double the 12,000 stuck at home a fortnight earlier.

And almost 28,000 Covid absences were recorded on December 23, the highest figure seen since NHS began publishing the data last month.

Mr Taylor said: 'The NHS is putting in plans to step up once again for patients with the new Nightingale surge hubs, extra support from community services and virtual wards, but there is no doubt the whole system is running hot,' he said.

'While the Government seems determined not to increase restrictions in England, it is vital we all behave in ways that will not exacerbate an already dangerous situation.'

NHS England national medical director Professor Stephen Powis said the health service is setting up the Nightingale surge hubs at hospitals across the country and recruiting thousands of nurses and reservists.