The Department of Health will have to replace two of the most senior figures who were at the forefront of the battle against Covid-19.
Deputy Chief Medical Officer Dr Ronan Glynn is resigning and leaving his role at the end of the month.
Dr Glynn, who's a native of Oranmore in Galway, is reportedly taking up a role with consultancy firm EY later this year.
Taoiseach Mícheal Martin and the Health Minister Stephen Donnelly have both paid tributes to Dr Glynn for his role during the pandemic, and his commitment to protecting public health.
It follows the decision of the Chief Medical Officer Dr Tony Holohan to retire in July.
The Health Minister is now facing questions from the Opposition as to whether Dr Glynn's decision not to remain in the public service was related to the botched secondment of Dr Holohan to Trinity College Dublin.
Social Democrats co-leader Roisin Shortall says questions must be asked of the Minister about the departure of the two most senior people tasked with leading the public health response to Covid-19.
Priscilla Lynch, Clinical Editor of the Medical Independent, says there will be a number of issues to consider when deciding on replacements...