People who are immunocompromised will be offered a third dose of a Covid-19 vaccine from next week.
The HSE says those who have a functioning immune system need just two shots to reach the required level of immune response.
But those who have a compromised immune system, such as certain cancer patients or people on certain medication require three shots to reach the required level of immune response.
Consultants will identify patients who need a third shot and will start contacting them from Wednesday next with appointments starting on Friday.
The Health Service says it is not the beginning of their general booster campaign though.
