After taking the oath of office and secrecy, the newly appointed health minister Gagan Thapa has assumed office on Friday.President Bidya Devi Bhandari administered Thapa the oath of office and secrecy as health minister at Sheetal Niwas this morning.Thapa has been picked from the Sitaula faction of the Nepali Congress. Gagan Thapa and Bhimsen Das Shrestha were in the race for one ministerial portfolio allocated for the Sitaula faction.