There is now high confidence that Omicron is relatively mild for most adults, says the UK Health Security Agency in its latest risk assessment.
This is largely thanks to vaccines providing high protection against serious illness caused by this latest Covid variant that is infecting many.
It comes as other data shows while , they are not very sick.
Meanwhile, Covid cases are on the way down, according to UK daily figures.
There were 99,652 new cases reported on Friday, a continuing drop which pushed the seven-day figure down by 29.5% on the week before.
It is too soon to say if the Omicron wave has peaked though, since the daily statistics are based on people who come forward for testing.
Prof Kevin McConway, Emeritus Professor of Applied Statistics at The Open University, said: "Infections often do not cause any symptoms, even though asymptomatic infected people can still spread the infection to others. Without symptoms people might not be routinely tested, and so end up not being counted."
There will also be some regional variation, with some parts of the UK running hotter with Covid than others.
Different figures, from the Office for National Statistics (ONS), estimate infection rates in the community by swabbing people regardless of whether they think they might be infected.
That data, which goes up to 7 January, suggests 4.3m in the UK have Covid. That's roughly one in 15 people and is the highest level of infections recorded by the ONS since the survey started.
The number of people testing positive for coronavirus fell in London, but increased in the North West, Yorkshire and the Humber, and the North East.
On Friday, the UK reported another 270 deaths of people who had tested positive for Covid within the previous 28 days. The seven-day total for deaths is up 67% on the week before, following a record spike in infections in recent weeks. Some of these will be people who died with Covid, not from it.
The The UK Health Security Agency (UKHSA) says the best way people can protect themselves and others against Covid, is to get fully vaccinated. People who need it can still get a first, second or third dose.
Susan Hopkins, Chief Medical Advisor at UKHSA, said: "A booster dose of the vaccine provides you with significant protection against hospitalisation from Omicron. Booster doses also increase the protection against symptomatic and asymptomatic infection, which will reduce transmission in the population.
"While prevalence remains high, make sure to wear your mask in indoor settings and take a lateral flow test before meeting others. If you develop any symptoms, isolate immediately and get a PCR test."