An estimated 2.4 million people are living with hepatitis C virus (HCV) in the United States, which makes for a national prevalence of about 0.84 percent. But according to a recent survey in JAMA Network Open, prevalence varies significantly from region to region, with western and Appalachian states bearing the brunt of the epidemic, Infectious Disease Advisor reports.

Analyzing the National Health and Nutrition Examination Survey, which conducts HCV testing among noninstitutionalized Americans ages 6 and older, researchers set out to estimate the prevalence of hepatitis C infection in each of the 50 states and the District of Columbia. Researchers noted that this information is not available through existing disease surveillance systems.

Using a multistep statistical approach and estimates for each state based on the survey’s sex, race/ethnicity, birth cohort and poverty strata data, researchers found a much higher prevalence of hepatitis C infection in western and Appalachian states compared with other regions. In fact, a total of nine states contained more than half (51.9 percent) of all the nation’s hepatitis C infections: California, Texas, Florida, New York, Pennsylvania, Ohio, Michigan, Tennessee and North Carolina. Five of these states were considered to be in the Appalachian region. What’s more, of 13 western states surveyed, 10 fell above the jurisdiction-level median HCV infection of 0.88 percent. Three of 10 states with the highest HCV prevalence were in Appalachia, researchers noted.

According to researchers, the results demonstrated significant hepatitis C prevalence both in regions with longstanding HCV epidemics and in states with newly emergent infections driven by the ongoing opioid crisis. States experiencing high rates of overdose often saw relative increases in estimated hepatitis C prevalence, whereas states with lower overdose rates saw HCV prevalence decline.

“These estimates help to quantify the need for investments in efficacious direct and indirect services for the prevention of HCV acquisition and transmission,” wrote study authors. “This includes syringe services programs…linkage to medication-assisted substance use treatment…direct medical services such as HCV testing and curative treatments [that] remain cornerstones for extending life and averting transmission.”

To read the full report and access state-by-state data on the hepatitis C epidemic, click here.