The cohort of 65 to 69 year olds has almost been completed, with 97 per cent given a first dose.
But just 44 per cent of those aged between 60 and 64 have so far been vaccinated, and many in that age group took to social media to ask if the rollout had “forgotten” them.
"Are we to be missed?” asked Edinburgh-based David Ramsay.
“I’m nearly 62 and still waiting in Aberdeen,” added Ann Palmer, while Argyll-based Elizabeth Rieve, 62, said neither she nor her husband had received a letter.
"The recent announcement of the next phase of the roll out has left me anxious that our cohort has been missed,” said Gill Tyson, 64, also from Edinburgh.
Professor of Immunology at Edinburgh University Eleanor Riley, 64, called the announcement “very worrying”.
"60 to 64 year olds in Scotland who are fortunate enough not to have any of the risk factors for severe Covid have been waiting patiently for our vaccinations whilst looking enviously at our contemporaries south of the border who had theirs weeks ago,” she said.
"We have had no indication when we will receive our invitations. To now hear that those between 55 and 59 will get their letters next week is very worrying. Have we been forgotten or is this more about the political messaging given that Scotland seems to be lagging behind again?”
Just over 1,809,000 people in Scotland have been given a first dose of vaccine, 41 per cent of the adult population.
Some 44 per cent of adults have had a first dose in England, compared to 43 per cent in Northern Ireland and 40 per cent in Wales.
First Minister Nicola Sturgeon said on Tuesday that Scotland is currently vaccinating 60 to 64 year olds, unpaid carers and those with underlying health conditions.
Vaccine supply is soon expected to increase from Monday, she said, with some stock needing to be used very soon.
“By now scheduling appointments for those age groups generally [55 to 59 and 50 to 54], we can ensure that no vaccine goes to waste,” she said.
Vaccination rates also vary by health board, with some smaller boards, such as NHS Western Isles, already vaccinating 50 to 55 year olds.
Many of those aged 60 to 64 who said they have not yet received a letter are based in the Lothians, which has one of the lowest rates.
David Small, head of the NHS Lothian vaccination programme, said the over 60s will not be left behind, and added that there will be some overlap in vaccination of different cohorts.
"To enable as many people as possible, to receive their vaccinations as quickly as possible there will be overlap in appointment between the different groups,” he said.
"We would like to offer our assurance, however that you will receive your vaccination when you are eligible.
“If you think that you should have received a vaccination, but have not yet received an invite, you should contact NHS Scotland.”