"Among the 4,136 case reports of acute hepatitis C received by CDC for 2019, data regarding risk behaviors or exposures were missing for 1,873 (45.3%) cases. At least one risk behavior or exposure was reported for 1,626 (39.3%) cases during the 6 weeks to 6 months before illness onset. More than one risk can be reported for each case.
"Among risk behaviors and exposures identified, injection drug use was most commonly reported (67% of the 1,952 cases for which injection drug use information was available). Hepatitis C virus transmission associated with surgery, dialysis, or transfusion is extremely rare in the United States; thus, the reporting of these exposures might represent a history of recent exposure to these health care procedures."
Centers for Disease Control and Prevention. Viral Hepatitis Surveillance Report – United States, 2019. Atlanta: U.S. Department of Health and Human Services; May 2021.