A health expert has said a five-day quarantine for all arrivals into Ireland would be more realistic and ensure more compliance.

Professor of Experimental Immunology at Trinity College Kingston Mills said quarantine is imperative as there are concerns that more variants of the virus will emerge.

He said the variants first detected in South Africa, Brazil and California are causing concerns as some have a mutation in the virus spike protein that makes it more difficult for the antigen in vaccines to neutralise it.

Speaking on RTÉ's Brendan O'Connor programme, Prof Mills said a five-day quarantine for international travellers from all countries, with a ban on anyone entering without a negative PCR test and a mandatory follow-up test five days later, would detect 99% of Covid-19 cases and be easier to implement.

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He said without variants Ireland could reopen sooner, but in the meantime people must work to reduce community transmission and that going forward the virus could be controlled with an annual booster vaccine.

Prof Mills said that Denmark is leading the way on IT to support its vaccination programme with a digital system integrated with an app on people's phone to register and record vaccinations.

As of Wednesday, 24 February, 391,355 doses of Covid vaccines have been administered in Ireland. 254,948 people have received their first dose and 136,407 people have received their second dose.

Minister for Foreign Affairs Simon Coveney said quarantine measures apply to all travellers into Ireland who are required to quarantine for 14 days.

Speaking on RTÉ's The Week in Politics, he said that travellers from non-Category 2 countries are allowed to leave quarantine if they get a second negative PCR test five days after arrival. 

"We are now moving to implement that from 32 countries, because there are an extra 12 countries to be added based on NPHET recommendations, that anyone coming from those countries that they will have to spend 14 days in a state-provided mandatory hotel quarantine," he said.

He said he hoped this would be implemented within the next two weeks and said Ireland has one of the most restrictive measures in the European Union.

Mr Coveney said that issues around international travel related to Northern Ireland must continue to be addressed and that the Government would like Sinn Féin's help in addressing these.

The minister also said Government communications with the public on Covid-19 have become "far clearer" in recent days. 

"Every country in the world is struggling with Covid and there's no country that hasn’t made some mistake and I think rather than focusing on those mistakes we should learn from them and do it better the next time and that’s certainly, I think, what you’ve seen this week on communications which has been far clearer in the last few days." 

Mr Coveney said that case numbers are coming down, "but it's gradual and it’s slow", but there is a trend now that allows the phased reopening of schools.

He said what drives the Government’s approach is to be sure "we don’t go backwards again"

Meanwhile, Sinn Féin TD Louise O'Reilly said mandatory quarantine should have been examined earlier.

"This does not go far enough. That is the anger people are feeling now, that they are doing their best, following all the guidelines but they feel let down by the Government who are not enforcing mandatory quarantine on all arrivals into the State," she said. 

Ms O'Reilly said that the "stay at home" quarantine is "nonsense" and test and tracing needs to improve with schools reopening.

Yesterday, the Department of Health reported 13 further coronavirus-related deaths and 738 new cases of the disease.

The median age of those who died was 81 and the age range was 55 - 92 years.

There were 311 cases reported in Dublin, 54 in Limerick, 36 in Cork, 34 in Offaly, 33 in Donegal and the remaining 270 cases are spread across 20 other counties.

In Northern Ireland, the Department of Health has reported 136 new cases of Covid-19 and a further three deaths in the past 24 hours.