Nicola Sturgeon has said the new coronavirus restrictions set to be announced later this week could last six months in some form.
Her comments came as the chief medical officer Dr Gregor Smith said that the chance of a vaccine being widely available in Scotland within the next six months was unlikely.
He added it “would not be wise” to hope a vaccine would arrive and bail the country out of more prolonged restrictions over the winter.
The First Minister said it would be necessary for Scotland to have restrictions for an extended period of time, but was not definitive about how long they would need to be in place.
She said: “We may be living for six months or that kind of time, I am not being absolutely definitive about that, where we need to have some kind restrictions.
"But it is not necessarily the case that we will be living under the same restrictions for a period of six months.
"It may be that we need to have variations and we will have periods where we can have fewer restrictions and periods where we may need more restrictions.
"Nobody can be definitive about this. Often we end up talking about time periods which, to some extent, are uncertain. We’re trying to give people as much of a degree of forward visibility as we can in an uncertain situation.
"Of course, six months takes us beyond the winter period as well where we know there are particular challenges in terms of transmission of the virus.”
Dr Smith added that there are positive signs coming out of vaccine trials ongoing around the country for vaccines that will be available to the Scottish Government and the UK more widely.
However he said all were still going through effectiveness and safety tests and that the logistical challenge of delivering them to the population meant it was unlikely mass vaccination would be possible within the next six months.
He said: “Those vaccines are still going through the tests of effectiveness and safety.
"As I have said on many occasions, there are some very encouraging signs in terms of the progress we are making with those vaccines.
"Over the next six months we’re in a period where there is likely to be a much higher risk of transmission.
"We can’t look at a vaccine as a way out of the situation that we find ourselves in.
"It is possible that we might start to see signs of a vaccine beginning to come through even within that spell but I expect given the huge logistics that are involved in the scale of the immunisation programme that would be necessary, it would not be wise of us to put all of our hope that a vaccine is going to see us through these winter months.”
The First Minister added: "Discovering a vaccine that works is one thing, manufacturing it in big enough quantities to vaccinate everybody and all of the logistics of that is a different thing completely.”