The First Minister said the current lockdown will continue until at least the start of next month, with the only change being the return of younger primary pupils to classrooms on Monday.
The vast majority of older children will remain at home until Mar 15 at the earliest and Ms Sturgeon warned Scots not to book Easter holidays as it "highly unlikely" that hotels or self catering accommodation will be open.
She even refused to guarantee that summer 'staycations' in Scotland will go ahead and warned that "our exit from lockdown is likely to be even more cautious than it was last summer."
Ms Sturgeon will next week unveil a new blueprint for "gradually" easing lockdown that will set out the "data", such as the Covid levels and test positivity rate, that will be required for her to consider easing specific restrictions.
Watch: Nicola Sturgeon: Statistics strongly suggest vaccines are cutting virus death toll
It will also detail the order in which they will be lifted, starting with schools, greater family contact and the "phased reopening of the economy". Non-essential retail will be prioritised.
But the First Minister has said Scots should not expect any dates to be included in the document and warned that Scots must endure "continued travel restrictions" for some time to come.
Despite boasting that Scotland last week had the fastest vaccination roll-out in Europe, she said that getting children back into education "may mean the rest of us living with some other restrictions for longer".
Scotland's business leaders welcomed an announcement by Kate Forbes, the Scottish Finance Secretary, that properties in the retail, hospitality, leisure and aviation sectors will not be liable for business rates in the coming financial year.
But the Federation of Small Businesses (FSB)warned Ms Sturgeon her blueprint must include dates, adding: "We can’t see local businesses collapse during the final mile of this marathon just because they don’t know the finish line is around the corner.”
The Scottish Tourism Alliance (STA) said her Easter comments were a "crushing blow to many" in the crisis-hit industry, with struggling firms also "extremely anxious" that she had placed a "question mark" over the summer season.
Ms Sturgeon's lockdown warning came as:
Her controversial hotel quarantine system wrongly detained two of its first international passengers - further exposing a "ridiculous" loophole.
An official audit found Scotland's fight against the Covid pandemic was hampered by the SNP government's failure to implement key recommendations from planning exercises.
It emerged nearly six out of 10 Scots aged between 65 and 69 have been vaccinated.
— Scottish Chambers (@ScotChambers) February 16, 2021🆕📢A revised strategic framework is long overdue - we will continue to work with @scotgov to ensure jobs are not low down the list of trade-offs.
Full statement: https://t.co/y7eRGwEAlb pic.twitter.com/B0BkuqFX1N
Ms Sturgeon told MSPs she was "very hopeful" that vaccination would start "significantly" reducing the number of Covid deaths, with some evidence this was already happening in care homes.
More than a third of Covid deaths occurred in care homes at the end of December but this had now fallen to 18 per cent, she said, while the number of cases in the community has dropped by around two-thirds since the start of the year.
But she insisted that "our situation is still very fragile", and the new variant meants that "even a slight easing of restrictions could cause cases to start rising rapidly again".
Ms Sturgeon admitted that "we cannot continue in lockdown indefinitely" but argued that "trade-offs" were required to ensure children could return to school.
She said "100 per cent normality" was unlikely "for quite a while" and warned "significant restrictions on our ability to travel overseas" were likely to be "inescapable."
A revised "strategic framework" on easing restrictions will be unveiled next week following talks with opposition parties, business groups and trade unions.
Ms Sturgeon said it would "set out as far as possible the conditions that need to be met, in terms of data, for us to start lifting restrictions."
In addition, she said it would "detail the broad order of priority for reopening", including a possible turn to the regional 'levels' approach with tiers of restrictions in different areas.
But she said the document would also be "clear about what we don't think will be possible for a while longer" and cited the example of Easter holidays "either overseas or in Scotland."
Ms Sturgeon said it was "highly unlikely" that foreign holidays in summer would happen despite a huge loophole that allows travellers to avoid her hotel quarantine scheme by flying from airports in the rest of the UK.
She said 'staycations" in summer may be possible, depending on "the data nearer the time", but refused to provide any guarantee.
Moving too quickly could mean another lockdown later this year, she argued, despite expressing confidence that the early May deadline for vaccinating everyone over 50 could be met early if supplies allow.
Ms Sturgeon said she wished she could be "firmer now about exactly when and how we will exit lockdown in the weeks ahead" but argued that "a cautious approach - however frustrating - will be more successful and more sustainable."
Dr Liz Cameron, chief executive of the Scottish Chambers of Commerce, said: “A revised strategic framework providing a routemap on the opening back of the economy is long overdue, but we will continue to work with Scottish Government to ensure jobs are not low down the list of trade-offs."
Marc Crothall, the STA's chief executive, said: "I know of numerous businesses who are wholly reliant on being able to trade again at Easter in order to stay solvent; today’s indication that this is highly unlikely will I know serve as a crushing blow to many."
Watch: COVID-19 - Foreign holidays 'highly unlikely' this summer, warns Nicola Sturgeon