Estimated Hepatitis C Prevalence and Viral Clearance Using Residual Sera From a Large Commercial Laboratory: November 2023–September 2024

BACKGROUND: Hepatitis C is a public health threat with national elimination targets, yet prevalence is challenging to measure. We utilized a novel approach to estimate hepatitis C prevalence among adults using residual sera from a large commercial laboratory. METHODS: We conducted a cross-sectional study in 50 states and the District of Columbia using a convenience sample of residual serum specimens (n = 81 483) among routine clinical specimens from adults aged 18-≤75 years. We randomly sampled within 2 age groups (18-≤49 years and 50-≤75 years) during November 2023-September 2024. Specimens were tested for hepatitis C virus (HCV) antibodies; reactive or equivocal results were reflexed to HCV ribonucleic acid (RNA) testing. We performed nested raking on the age-sex distribution of the United States. RESULTS: Among adults aged 18-≤75 years, we estimated that the HCV antibody prevalence was 2.9% (95% CI, 2.8%-3.0%), corresponding to 6 887 000 (95% CI, 6 622 000-7 166 000) persons ever infected, and the HCV RNA prevalence was 0.7% (95% CI, .7%-.8%), corresponding to 1 698 000 (95% CI, 1 554 000-1 845 000) persons currently infected. Viral clearance was lower among younger adults (63.8% [95% CI, 60.6%-66.9%]) than older adults (81.1% [95% CI, 78.9%-83.3%]). CONCLUSIONS: In this analysis of residual sera from a commercial laboratory, we estimated that approximately 1.70 million adults were diagnosed with HCV infection during November 2023-September 2024. Although underlying selection bias limits generalizability to the US population, the substantial burden estimated after a decade of available curative treatment underscores the need for concerted nationwide hepatitis C elimination efforts.