The national clinical director said the Scottish Government will take advice from its Education Recovery Group (ERG), chaired by Professor Linda Bauld, on when the time is appropriate to scrap masks in high schools. Primary school pupils do not have to wear masks.
Speaking on BBC Radio Scotland's Good Morning Scotland programme on Friday, Prof Leitch also said he believed a full lockdown in Scotland was unlikely, but warned there could be some “tricky moments” in coming months.
In recent weeks, First Minister Nicola Sturgeon has said there is reason to be optimistic about the trajectory of the Omicron variant, with Scottish Government projections for daily infections not being met.
Ms Sturgeon this week said Scotland had “turned the corner on the Omicron wave”.
Asked when school children will be able to take their masks off, Prof Leitch said: “I honestly don’t know.”
He said “the ERG do not want face coverings in secondary schools “unless that is the safest thing to do, adding: “They’ll give us advice to remove them when they think it’s appropriate and I think that day is coming.”
Prof Leitch said he cannot see a return to the tough restrictions put in place earlier in the pandemic.
“I don’t think we’ll go back to full lockdowns,” he said.
“I can’t tell you for sure – nobody knows for sure – but my reading of the science, the history of pandemics, the global research that’s going on would suggest that the very original days – now some two years ago unbelievably – where we were locked in our houses … I don’t think we’re heading back there.
“But I think we might have tricky moments on the road out, but I’m hopeful today because Omicron is diminishing.”
This week, Ms Sturgeon announced the remaining restrictions imposed to tackle the Omicron strain, which include caps on crowds at events, social distancing in public places and table service in venue where alcohol is served, will end from Monday.
However, face masks will still be required in public places and Government guidance continues to urge people to work from home, along with self-isolation requirements and the vaccine passport scheme for some venues.