The health board said a “data error” caused 2,500 text messages to be sent to teenagers in Lothian inviting them for a second dose.
Currently, in line with national guidance, 16 and 17-year-olds in Scotland are only being offered one dose of the vaccines unless they are clinically extremely vulnerable themselves, living with someone who is, or are an unpaid carer.
The health board said on Friday it has sent a second text message urging the teenagers not to attend unless they fall into one of the above categories.
NHS Lothian is investigating the situation to establish what happened and how many letters have been sent via the national booking system to teenagers.
Pat Wynne, the health board’s nursing, primary and community care director said: “I would like to apologise to all of those teenagers affected and for any confusion and inconvenience caused.
“All of those who received a text message have been contacted again with more information on what to do next.
“We don’t yet know how many letters have been issued, but we are investigating fully to establish what happened and how many people are affected.
“If you are eligible for a second dose, if you are clinically extremely vulnerable yourself, living with someone else who is or are an unpaid carer, please double-check your appointment and make sure you receive that vital protection from a second dose.
“However we are really keen to make sure that other teenagers do not face a wasted journey to a vaccination centre or that they do not receive a second dose when it is currently not recommended for them.”
So far 4,194,212 people in Scotland have received their first dose of a Covid-19 vaccination and 3,840,251 have had their second.
Meanwhile the Office for National Statistics estimates that around one in 55 people had Covid-19 in the week to September 25, down from one in 45 the previous week – which had been the highest level since estimates began for Scotland in October 2020.