The highest rates of acute cases of hepatitis C in the U.S. were among young adults and millennials in 2018, researchers found.
Annual rates of acute hepatitis C cases were highest among younger adults ages 20-29 (3.1 per 100,000) and ages 30-39 (2.6 per 100,000), reported A. Blythe Ryerson, PhD, MPH, of the CDC, and colleagues.
Moreover, the highest proportions of newly reported chronic hepatitis C cases were among adults ages 20-39, as well as ages 50-69, the authors wrote in the Morbidity and Mortality Weekly Report.
Last year, the U.S. Preventive Services Task Force (USPSTF) recommended screening of all adults ages 18-79 for hepatitis C virus (HCV) infection -- not just baby boomers as the previous recommendation stated. The CDC now recommends screening at least once for adults ages 18 and older, screening every pregnant woman during pregnancy, and regularly testing all individuals with risk factors.
The researchers noted that while historically, HCV infection was highest among baby boomers, the opioid epidemic is likely why new infections have shifted to younger adults, including those of reproductive age. In addition, HCV infection is often asymptomatic, which could increase the risk of transmission to others, the authors noted.
For this study, they examined data from the National Notifiable Diseases Surveillance System from 2009 to 2018 by age group to determine the number of acute HCV cases per 100,000 reported to CDC. The team also looked at data from the National Health and Nutrition Examination Survey (NHANES) to estimate the proportion of adults with HCV who had been told they had hepatitis C.
Overall, 3,621 hepatitis C cases were reported, for an estimated 50,300 cases (95% CI 39,800-171,600), the authors said. They also noted a jump in the number of acute cases per 100,000 from 2009 to 2018 (0.3 to 1.2, respectively).
During that time period, the researchers found a 300% increase in HCV cases among adults ages 20-29 (0.7 to 3.1 per 100,000, respectively), and about a 400% increase among adults ages 30-39 (0.5 to 2.6 per 100,000).
There were 137,713 new cases of chronic hepatitis C reported during 2018, the authors said -- about two-thirds in men. While baby boomers accounted for 36.3% of cases, millennials (born between 1981 and 1996) accounted for 36.5%, and Generation X (born between 1966 and 1980) for 23.1%. The authors also found that 60.6% of 2015-2018 NHANES participants ages 20 and older who were HCV-RNA positive reported being told they had hepatitis C.
Limitations to this data, the researchers said, include that the number of cases underestimate the incidence of disease, that not all states reported HCV data to the CDC in 2018, and that the sample may not be representative because it excludes high-risk groups, such as incarcerated persons.
Disclosures
The authors disclosed no conflicts of interest.
Primary Source
Morbidity and Mortality Weekly Report
Source Reference: Ryerson AB, et al "Vital Signs: Newly Reported Acute and Chronic Hepatitis C Cases -- United States, 2009–2018" MMWR Morb Mortal Wkly Rep 2020; 69: 399-404.