With the new variants and the mutating nature of the coronavirus, Dr Gregor Smith said boosters may be needed in addition to the massive population rollout that is currently underway.

So far more than 1.6m people in Scotland have received their first dose and more than 35,000 have had the second dose.

Some people, it has been suggested, may need to go through the vaccination experience again.

Dr Smith said: “What we don’t have yet is a full assessment as to how long that vaccination will confer immunity and, once we know that, we’ll know exactly when booster doses may or may not be required.”

Studies are ongoing into how effective the vaccines are to the new variants, particularly the one from Brazil found in three people in Scotland, who took flights from Brazil to Aberdeen via Paris and London.

Dr Smith added: “The additional element that’s now started to come in, very strongly, to the mix, is about what are the impacts of these new variants of concern we’re beginning to see.

“Because some of those have features in them that may mean it’s more likely that the virus can begin to show what we call immune escape, either away from natural immunity, or from the vaccine immunity that we give from the vaccination programme.

“I think it’s reasonable to suspect there will be an ongoing need for some sort of vaccination programme in some form over the coming years.”

He said it is not known how long it would be before a booster was needed as that was dependent on how quickly other variants become apparent and established.

He added: “I suspect that vaccination against the Sars Cov-2 virus is something that we’re going to be contemplating from this point in, particularly if we continue to follow a programme where we suppress the virus to as low a level as possible, not just in this country, but globally.”

The latest vaccinations statistics showed another 27,518 had a first dose on Tuesday taking the total to 1,661,879 people in Scotland.

Another 8,105 people received second doses on Tuesday, taking the total to 35,623.

Health Secretary Jeane Freeman said planning was underway to understand how many people would need to be jabbed again.

She said it was not yet clear who would need to be given another course of vaccination.

Freeman said: “The planning is underway to indicate the scenarios underneath that reasonable expectation of a repeat of the current scale of the vaccination programme - 4.45 million adults in Scotland - at one end, to the possibility that it may be a small number at the other end.

“It depends on all that evidence and information and knowledge that will come through people like Gregor to me and to us.”

The latest daily statistics showed there were another  543 positive  cases recorded which was 2.6% of the total number of tests, 

It takes the total number of confirmed cases in Scotland since the pandemic began to 203,555.

Of the new cases, 150 were in Greater Glasgow and Clyde, 77 in Lothian, and 102 in Lanarkshire.

The remaining cases were spread across 8 other health board areas.

The number of people in hospital and the number in intensive care has fallen.

There were 750 people in hospital, which is 34 less than the previous day.

There were 69 people in intensive care, a reduction of 2 from the day before.

Another 35 deaths were registered of someone who first tested positive over the previous 28 days.