Talk to Gastroenterologist on Hepatitis C

Hi my mother is on hepatitis medication since her PCR is positive.. it's been one month and PCR test has come negative but our treating doctor has instructed to continue the course. I want to ask once insha'Allah the course is done and her reports are still negative can the virus attack again? If so what are the precautions available. To my knowledge their is no vaccination for hepatitis C.