As fresh Level 5 restrictions come into effect amid record case numbers, here are five key points from the last Department of Health briefing of 2020.

4,000 additional cases in system

Prof Philip Nolan said that there are as many as 4,000 additional positive cases in the system, which have yet to be reported.

He said in recent days over the festive period, there were "very few people" presenting for tests, which meant fewer positive tests coming from labs.

He said they estimate there is "somewhere in the region of 4,000 positive tests" reported in the past 2-3 days which have yet to be formally confirmed as cases.

"Simply put, this system was not designed to report 2/3/4,000 tests per day, and it is going to take several days to confirm all of those cases," he said.

Close contacts will not be tested

The Chief Medical Officer said that close contacts of a confirmed case are now not advised to seek a Covid-19 test.

However, they are still told to restrict their movements for 14 days, and contact their GP immediately if they develop symptoms.

"We are once again in the mitigation stage of this pandemic," said Dr Tony Holohan.

"To support the testing system through this surge, we are no longer advising close contacts of confirmed cases to get tested. Testing and tracing is an exercise in containment and we are no longer in a containment phase. However, it is imperative that if you are a close contact of a confirmed case you restrict your movements and contact your GP immediately if you develop symptoms," he said.

Pressure on health system

The current rates of transmission are putting severe pressure on health services, according to the HSE's Dr Colm Henry.

Prof Philip Nolan said the R number remains at least 1.6-1.8, while the growth rate stood at 7% to 10%.

Even if we suppressed the virus and brought the R number below 1, he said a peak of between 700-1,000 people in hospital was expected by mid-January.

He said if we fail to suppress it, then we would face "an intolerable situation" in hospitals.

"The number of cases are so high that we are experiencing delays in reporting them," he said.

"We must suppress transmission. There is no alternative," he said.

Recent positive cases had up to 30 close contacts

Dr Tony Holohan said some examples of recent cases of Covid-19 have shown that 20 or 30 close contacts were identified.

"Clearly not in any way following the public health advice," he said.

Everyone should behave as if they are a close contact now, added Dr Holohan.

52,000 would be eligible for testing under current criteria

If everybody was referred for testing based on the criteria that existed today, the HSE's Chief Clinical Officer Dr Colm Henry said there would be 52,000 people referred for testing.

He said this is "not sustainable".

The sheer number of close contacts identified is now so high, that it is putting intense pressure on the testing and tracing system.

This goes some way towards explaining why health authorities decided to scale back testing of close contacts.