Self-isolation and testing rules will change after 19,290 new cases are reported.

According to a January 6 letter from Chief Medical Officer Dr Tony Hollohan to Health Minister Stephen Donnelly, up to 500,000 Irish people were likely infected with COVID-19 last week.

Dr Holohan told Mr Donnelly in the same letter that the chance of active infection was 5.7-9.6 percent, which equated to between one in 10 and one in 20.

Its contents came as 19,290 new cases of the virus were confirmed on Tuesday. As of 8 am on Tuesday, there were 1,062 patients in hospitals across the country, of whom 92 were in ICUs.

Despite the continuing high case numbers, Mr Donnelly has said that people who have received a positive COVID-19 antigen test result will no longer need to obtain a confirmatory PCR test.

Until now a positive antigen result required people to have a PCR test to confirm a positive result, but the change would free up space in the testing system.

Mr Donnelly also confirmed that he plans to bring to cabinet a five-day isolation period for close contacts of confirmed cases if the person has been given their COVID-19 booster.

Mr Donnelly told Newstalk FM that he received the recommendations on Tuesday afternoon in a new letter from Dr Holohan dated 11 January.

Close contacts who have not received a booster and are in contact with a confirmed COVID-19 case will now have to isolate for seven days.

For those who have actually tested positive themselves, the isolation period for all will now be reduced from 10 days to seven. Previously it was seven days for those who had a booster, and ten for those who did not have a booster.

In addition, anyone who has not received a booster shot but who has had COVID-19 in the past three months will not have to restrict their movements for five days if they have been in close contact with a confirmed case.

This is set to have a major impact as large numbers of people in the coming weeks will no longer need to restrict their movements if they are believed to be in close contact.