Professor Jason Leitch has told MSPs he believed this was the "most likely scenario". He said that science would provide an answer to the Covid-19 pandemic.
It is anticipated that a vaccine for the virus will be ready towards the end of this year or early next year, with Astrazeneca's Oxford University devised treatment among the forerunners for approval.
The senior medic was quizzed by SNP backbencher Margaret Ewing about what will constitute "success" in the battle against the virus as he appeared before Holyrood's Covid-19 committee today.
"Science will get us out of this," Prof Leitch said.
"Crowds will come back to stadia and we'll back out in restaurants and the pubs will be full. I have absolutely no doubt that that will come, that there is hope.
"I don't know when it will be. I think the most likely scenario for that to begin is the spring of 2021 and into the summer of 2021, but I don't know that for sure."
Prof Leitch said talks were underway among medical advisors across the UK about a "levels-based system" that would provide a measure of medium-term success in keeping the virus under control.
"There are attractions with that," he said.
"It's very clear, it's understandable, it's easy to communicate."
There could be problems with such an approach as the virus does not operate in "factors of 50 or factors of 20", meaning sudden outbreaks could skew the figures.
But Prof Leitch said: "We quite like the idea of the clear communication of a levels system."
The medic also admitted that advice to restrict on care home visits and the ban on entering other households across Scotland were the "most difficult" he has had to provide to the First Minister.
"It is unprecedented for a public health advisor to tell decision-makers in a country that you cannot visit your mum or your children or have your adult children around."
But he added: "The reality is every time two separate households come together, there is risk."