One witness, a haemophiliac using only the name "Mark", told the inquiry how he had been infected with HIV and hepatitis C after being treated at Edinburgh Royal Infirmary in 1984, when he was 13. He said medics did not tell him that he had contracted the condition for seven years.
He said: "They knew I was HIV positive and had hepatitis C but kept quiet. They've taken my life away from me. When they finally told me I was open-mouthed in disbelief. My life has been ruined."
The inquiry also heard from "Elaine", whose husband died in 1992, six years after he was diagnosed with HIV as a result of a blood transfusion at Edinburgh Royal Infirmary.
She said she had lived for two years with the infection before being told by doctors.
"This scandal has taken a soulmate, a great father and a loving grandfather from us. This should never have happened and should never be allowed to happen again," she said.
The inquiry into the outbreak of clostridium difficile at the Vale of Leven hospital, which infected 55 patients between December 2007 and June 2008, also heard evidence from witnesses.
Michelle Stewart, who helped set up the C-Diff Justice Group, said the hospital was unable to give basic personal care to her mother-in-law, Sarah McGinty, 67, who died on February 1 2008.
She told the inquiry: "One of the big questions we've got is why an infection was allowed to run rampant for six months without detection?"