It will be early next year before life in Northern Ireland returns to relative normality, the Chief Medical Officer said.
From 70% to 80% of the population will need to be vaccinated with two doses.
Some 16% of those most vulnerable to Covid-19 have received a first jab so far.
The new variants would spread like a “finely-tuned sports car” if restrictions were eased too quickly, Dr Michael McBride added.
He said: “I think we will have restrictions in place next autumn and winter.”
He said they may be less onerous than at present and hoped the coming summer could be somewhat like last summer when curbs were eased.
“I am cautiously optimistic but we need to be realistic that the current restrictions we have in place are likely to be in place for a significant period of time.”
He said the health service was in a “fragile” place, with 579 people still in hospital with Covid-19, and warned infectious new variants clouded the picture.
The arrival of the South African variant is expected in the future and is already in the Republic of Ireland.
Dr McBride added: “The virus does not read the rule book, it does not follow our timelines.”
The criteria for relaxing restrictions includes:
– Those most at risk having been vaccinated
– Those around the most vulnerable groups have also been inoculated
– Community transmission levels are low.
If restrictions were eased now we could see exponential growth and another wave of hospital admissions, Dr McBride added.
He said: “We are driving a different car now.
“It may have been a Ford Fiesta with the old variant but this is a highly-tuned sports car with the new variant.”
Patricia Donnelly, who leads the vaccination effort for the Department of Health, said the take-up of booking slots among those aged 65 to 69 had not been as fast as hoped for.
Nearly all care home residents have received a second jab, bar those which were dealing with an outbreak.
Plans are being progressed to see the clinically extremely vulnerable at mass vaccination centres.
Mass gatherings are banned to curb the spread of coronavirus.
Meanwhile, young officers who intervened following the Sean Graham bookmakers shooting commemoration did not intend to cause offence, the Police Federation in Northern Ireland said.
One was suspended and another repositioned following Friday’s incident in Belfast’s Ormeau Road.
Federation chairman Mark Lindsay said the police had no idea of the sensitivities involved and had asked advice from more senior colleagues after noticing a crowd while driving by.
He said: “These two officers under no circumstances went there to cause any offence or any hurt.
“They were simply unaware of it.”
A further 10 people have died after testing positive for Covid-19 in Northern Ireland.
Department of Health figures on Tuesday also notified another 275 new cases of the virus.
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-- to www.belfastlive.co.uk