People aged 12 and over who have a weakened immune system will be offered an additional dose of the Covid-19 vaccine, the HSE has confirmed.
This comes after the health service's chief executive Paul Reid said the rollout of the booster jab will begin on Friday.
Today's announcement means all those who have a weakened immune system will receive another jab, including those with certain underlying health conditions, or people receiving specific treatments which cause them to be immunocompromised or immunosuppressed and therefore have a reduced response to the vaccine.
"It has been shown that people with weakened immune systems do not generate a full immune response to their first two doses of the Covid-19 vaccine," the HSE's chief clinical officer Dr Colm Henry said.
"This additional dose we are offering will mean they will get the maximum benefit from their primary vaccination course, giving them better protection against the serious effects of Covid-19."
The HSE confirmed hospitals will identify people who need to receive an additional dose of the vaccine. People will not have to register or contact their GP/hospital in order to receive the vaccine but will instead receive a text message with an appointment date.
The additional dose will be given at the person's local vaccination centre, the hospital in which they are a patient, or through their GP.
The booster jabs will first be administered to people aged 16 and over before extending to those aged 12-15, as this age cohort received their first course of vaccination more recently and have not reached the two-month minimum interval since their last dose.
The HSE added that regardless of what vaccine the person received for their initial course they will receive a single dose of an mRNA vaccine (Pfizer-BioNTech or Moderna) for their booster jab.
