Northern Ireland's chief medical officer has warned the current third wave of the pandemic "will get worse before it gets better" and urged the public to assume everyone they come into contact with has Covid.
Dr Michael McBride was speaking following a weekend in which hospitals were stretched to their limits due to Covid pressures.
In a joint statement issued on Sunday night, the heads of Northern Ireland's health trusts said that the number of people with Covid-19 in hospital will double by the third week of January compared to the current figures.
Speaking on the BBC's Nolan Show, he said increased family mixing and contacts over the Christmas period has resulted in an increase in community transmission.
"It was inevitable that some of that would translate into cases. Over the last few weeks we have seen cases almost double, and I think it is fair to say that we will now see a doubling of inpatients with Covid," he said.
"In the run-up to Christmas we saw about 500 people in hospital with Covid at any one time and I think it is likely we will soon see this in excess of 1000, putting extreme pressure on already hard-pressed staff."
Dr McBride said this will mean some "very difficult choices" will have to made, including turning down other clinical care, due to the pressures facing the system.
"Be in no doubt, the decisions you make today, tomorrow, the decisions you make in terms of the number of contacts that you have, will make a difference in terms of whether or not you will continue the change of infection, which could result in a older person getting Covid, which could then result in an admission to hospital.
Dr McBride said the real issue is staffing, as Covid patients require specialist care and diverting resources from one part of the health service means other areas will suffer.
"Things are bad now, and they will get worse before they get better. I anticipate we will see sustained pressure on our health service and those are difficult pressures for staff to withstand," he said.
"Staff will be stretched physically, mentally, in ways they have never experienced before.
"People need to stay at home, people need to reduce their contacts - there should be no unnecessary contacts. Every time you leave your home, if it's not for work, essential travel or exercise, and every time you come into contact with another person you must assume the person you are coming into contact with has Covid.
"We are in an emergency situation our hospitals are under extreme pressure. Our healthcare staff will not be found wanting, they will do everything they can to ensure they can provide acute care... We will do everything we can to ensure the quality of our care is not compromised, but there can be no guarantee given the pressures our healthcare system is under."
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