Coronavirus vaccinations for the over-70s have begun, with two mass vaccination centres opening in Edinburgh and Aberdeen.
The Scottish government has said everyone in the next stage of the vaccine rollout should receive their first jab by the middle of the month, subject to supplies.
Initially, the new centres will be able to vaccinate 27,000 people a week.
Over-70s will also receive jabs at smaller centres such as village halls.
Some GP surgeries have already begun the vaccinations for that priority group, which also includes people who are clinically extremely vulnerable and over-16s on the shielding list.
Letters started going out a week ago and the Scottish government is urging everyone to take up their appointments.
The site at the Edinburgh EICC will be able to vaccinate more than 21,000 people a week, while the Aberdeen facility at P&J Live will vaccinate about 6,000 every week.
The Louisa Jordan mass vaccination centre in Glasgow has been operating since 8 December.
It has been carrying out between 1,000 and 5,000 vaccinations daily and has the capacity to move to 10,000 a day.
The Scottish government said the scale of operations at the mass vaccination centres meant letters would also start going out next week in Lothian, Grampian and Greater Glasgow and Clyde to those aged between 65 and 69 – the next group on the priority list.
It said the programme for first doses for care home residents, front-line health and social care workers and those aged 80 and over would be completed by 5 February.
Health Secretary Jeane Freeman said: “It is testament to all those working hard to roll out the vaccination programme that major logistical operations such as these are up and running despite the current restrictions.
“I would urge everyone to take up their appointment when they are offered one. The vaccination programme is one of three key ways we are working to beat this virus, along with our expanded testing programme to identify cases and break chains of transmission and the important lockdown restrictions everyone in Scotland must follow.
“All these measures work to greatest effect when they work together.”
The Scottish government’s vaccine deployment plan, which was published on 14 January, said vaccination facilities would also open in Bathgate, Musselburgh and Motherwell, however, no specific dates have been given.
NHS Lothian has told BBC Scotland that the Bathgate and Musselburgh sites will be able to carry out about 14,000 and 8,000 vaccinations per week respectively when they are fully operational.
The virus programme was boosted on Saturday as NHS Lanarkshire opened the doors in East Kilbride to any over-80s who had not yet received their first dose.
The health board advertised extra appointments at its vaccination centre at the Alistair McCoist Complex for patients of GP practices in the area who were eligible .
Last week, the Scottish government said it was “on track” to meet vaccine targets.
It has pledged to publish historic vaccine figures, such as how many doses were promised and how many were delivered, from next week.
The UK government had rebuked the devolved administration for publishing such data earlier this month, claiming it could be commercially sensitive.
Speaking on the BBC’s Politics Scotland programme, Scottish Secretary Alister Jack said he did not believe the Scottish government should publish future vaccine supply data.
“I said this to the first minister in a phone call last night, I think the number that should be published is the historical data of what’s available to the Scottish government, which will be north of one million,” he said.
He added that this week there would be about 1.15 million doses of the vaccine in Scotland while only 551,008 had been injected so far.
Mr Jack said the vaccine was held in a central site for the whole of the UK, with doses delivered the next day at the request of the Scottish government.