The health minister said it was a “lonely and challenging position” as the sole Ulster Unionist minister in the executive during the pandemic.
Mr Swann was appointed health minister in January 2020 when power sharing at Stormont returned.
But he added that on recollection it was also a “strength” as he did not have to answer to party political colleagues.
He said that during the pandemic, he believed he did have support from other parties.
First Minister Michelle O’Neill is due to give evidence on Tuesday, with her former partner in the Executive Office, Baroness Foster due to appear on Wednesday.
During the pandemic, Ms O’Neill was deputy first minister from January 2020 until February 2022, while Baroness Foster was first minister from January 2020 until June 2021.
The inquiry is due to conclude sitting in Belfast on Thursday, when Sue Gray, who is now chief of staff to Sir Keir Starmer, is due to give evidence.