Health officials need to reconsider allowing the use of the AstraZeneca and Johnson and Johnson vaccines for younger people, according to the Taoiseach.
Micheál Martin believes the Delta variant has changed the balance of risk when it comes to using those vaccines.
The National Immunisation Advisory Committee is set to examine changing the recommendations for use among younger age groups.
The Johnson & Johnson and AstraZeneca vaccines are currently recommended for older age groups because of concerns about very rare cases of blood clots.
Taoiseach Micheál Martin says the policy might need to change to keep up the pace of the roll-out through the summer:
"That would really broaden the portfolio of vaccines available for July and August. I think the balance of risk has changed, so that's something that will be considered by the immunisation advisors to Government in terms of making sure we can protect people against the Delta variant", he said.