The European Medicines Agency is due to give a verdict on the safety of the Johnson and Johnson vaccine later today.
It follows reports of rare blood clotting events in the United States.
HSE CEO Paul Reid said last week's that doses of the single-shot vaccine had arrived in Ireland, but are in "quarantine" awaiting the verdict from the EMA.
US health regulators recommened the use of the vaccine should be stalled to allow an investigation into six cases of rare blood clots in women.
More than seven million doses of the inoculation have been administered in the US.
Last night, the Acting Chief Medical Officer Dr Ronan Glynn said there won't be a decision made here on changing the interval period for the Pfizer and Moderna vaccines until the EMA's decision is made.
The group is to hold a briefing in Brussels at 4pm Irish time.
