There have been 29 reports of people in Ireland developing blood clots after getting the AstraZeneca Covid-19 vaccine.
The state's medicines regulator says less than five were also associated with low platelets.
Blood clots, with low platelets, are a very rare but possible side-effect of the AstraZeneca jab.
The HPRA has received 41 reports of people developing blood clots after getting the Moderna or Pfizer vaccines - but without low platelets.