There have been a further 126 cases of Covid-19 confirmed in Ireland, the Department of Health has said, bringing the total number of cases here to 683.

Three people who have been diagnosed with Covid-19 have died since the outbreak began here, and of those two had a reported underlying medical condition.

The department said 12 people diagnosed with Covid-19 have been admitted to intensive care units and 140 people overall have been hospitalised.

Speaking at a press briefing, Chief Medical Officer Dr Tony Holohan said the hope is that by the end of the month figures will reflect the impact of social distancing measures.

"Now is not the time for complacency," he said. "Every citizen who is practicing social distancing, who is taking precautions to limit the spread of this virus, is doing their country a service."

Dr Holohan said: "There is going to be an increase in the number of cases. 

"There is going to be an increase in hospitalisations and there is going to be an increase in the number of ICU admissions. All of that is going to create a challenge for the health service."

It is for this reason, he said, that Ireland is "instituting these measures as a society" in order to have a slower rate of growth and a smaller peak.

He said that at the moment there is no justification for introducing a "lockdown" and added that there is a high degree of compliance in society with the social distancing and other measures already introduced. 

Dr Holohan said that we need to wait and see what the impact of these measures will be.

He said that people would understand a "lockdown" to be severe and may mean not leaving the house to work or do any other social activity and these are "very severe" and "draconian" measures.

"I don't think at this moment in time, on the basis of what we have, and high compliance, that we have a justification for stepping up to something like that," he said.

He added if the percentage of cases is failing day-on-day by the end of the month this would be regarded as a positive.

Dr Holohan said it is too early to put interpretation on figures, saying they are small numbers relative to what we are likely to see and as the number of cases grow, we will get more stability in the data, allowing for more "reliable" projections.

"I would not want people to take a conclusion from either yesterday or today's figures," he said, adding that the cases so far all relate to people who became infected prior to the introduction of social distancing measures.

He also said he was encouraging people to take "personal responsibility" to continue observing social distancing measures.

Dr Holohan said the number of tests being carried out is increasing day-by-day, while there has also been an increase in the number of laboratories analysing tests.

Earlier, health authorities in Northern Ireland said nine more people were diagnosed with coronavirus, bringing the total there to 86.

One person diagnosed with the virus has died in Northern Ireland, bringing the total number of deaths on the island of Ireland to four.

Overall, 769 have been diagnosed with Covid-19 on the island.

Around 80% of cases of Covid-19 will be a mild to moderate illness, close to 14% have severe disease and around 6% are critical.

Generally, you need to be 15 minutes or more in the vicinity of an infected person, within 1-2 metres, to be considered at risk or a close contact.

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The Health Protection Surveillance Centre has released data based on the 438 confirmed as of midnight on Wednesday 18 March.

Of the 438 cases notified, 55% are male and 43% are female, with 27 clusters involving 142 cases.

The median age of people diagnosed with the virus is 44.

It said 32% of cases have been hospitalised, with 2.7% admitted to intensive care. This means that 8.6% of all cases have seen patients hospitalised.

One in four cases (114) are associated with healthcare workers, 36 of which are associated with foreign travel.

Dublin has the highest number of cases at 51%, followed by Cork 15% and Limerick and Wicklow have 3% of cases each.

Monaghan is the only county where a case had not been confirmed as of midnight on Wednesday.

President Michael D Higgins has signed into law emergency legislation passed by the Dáil and Seanad.

It gives the State new powers to detain people, restrict travel and keep people in their homes during the Covid-19 crisis.

The Taoiseach has said the restrictions being imposed on people to try to stop the spread of Covid-19 are "absolutely necessary" to protect human life and health.

Leo Varadkar was speaking at the graduation of more than 300 gardaí at the Garda College in Templemore as part of exceptional policing measures to deal with coronavirus.

A total of 319 students, some of whom have only been in training in Templemore for the last few weeks, have been sworn in as gardaí and assigned to stations all over the country.

Their tutors and instructors - 124 gardaí, sergeants and inspectors - are also being deployed to frontline policing in response to Covid-19.

Meanwhile, Irish people overseas who wish to return home have been advised to do so as soon as possible while commercial flights are still an option.

Tánaiste Simon Coveney said "flight restrictions and route cancellations are happening on a daily basis worldwide" due to the Covid-19 pandemic.

Separately, the Health Service Executive has said 900 new ventilators have been ordered for use with patients with Covid-19 and some of those will be delivered by the end of the month.

That is in addition to the 1,229 machines currently available in the country.

Chief Clinical Officer at the HSE Dr Colm Henry said the Department of Health has secured a "steady stream" of Personal Protective Equipment for healthcare workers.

This includes 6.5 million face masks, 4.5 million respiratory masks and over one million goggles.