Hepatitis C (HCV) is often referred to as the hidden epidemic, because many people who are infected don’t know it. A recent study suggest that this nickname is not without cause, finding that the rate of people infected with HCV who don’t know it is higher than for people with HIV, the virus that causes AIDS

HCV affects an estimated 3.5 million people in the United States — many of whom are asymptomatic and don’t know they are infected. Chronic infection can cause liver fibrosis (scarring), cirrhosis and cancer. While treatments for HCV have cure rates of 95 percent or higher, beginning treatment before liver damage occurs is key.

The study, published in the American Journal of Public Health, found that 19 percent of individuals, who had not already been diagnosed with HCV, when screened, were in fact infected. This rate of undiagnosed infection — at nearly one in five people — was almost double the rate previously estimated by the city of New York for its populace. By comparison, the prevalence of undiagnosed HIV was 0.2 percent.

The study was conducted by experts from the Centers for Disease Control and Prevention, the New York City Department of Health and Mental Hygiene and Quest Diagnostics. They performed the analysis on individuals screened in connection with unrelated health services in an emergency department in a busy hospital in New York City. They believe the findings suggest “that aggressive testing initiatives similar to those directed toward HIV should be mounted to improve HCV diagnosis.” For several years, New York State law has mandated the offer of voluntary HIV testing in hospital emergency departments, but not for HCV.

“Too often patients do not receive appropriate screening for infectious diseases, such as HIV and hepatitis C, in primary care settings. The present study shows that screening patients for HCV in an emergency care setting, following the model in place for HIV, is feasible and can reliably identify infected individuals,” said Rick L. Pesano, M.D., Ph.D., vice president, research and development, Quest Diagnostics, which analyzed data for the study. “That’s a highly significant finding as identifying these individuals is the first step to getting them into the right care and curing the infection. It should spur more dialogue about the merits of replicating the success of the emergency care model of HIV screening for hepatitis C.”

The new research emerged from an ongoing collaboration between the CDC and Quest Diagnostics to enhance population health initiatives for hepatitis B, C and other strains. Quest helped analyze the laboratory test results and provided related expertise. Quest provides a broad range of hepatitis testing services to aid diagnosis and treatment of hepatitis — find out more at KnowAboutHepC.com.

In recent years, the CDC has recommended that individuals born between 1945-1965 — so-called “Baby Boomers” — are at heightened risk for hepatitis C, and should receive one-time screening. However, the new study suggests that broader population screening for hepatitis C may be appropriate.

“The low proportion of HIV-infected but undiagnosed persons found by the serosurvey follows a period in which NYC mounted and funded initiatives to increase routine HIV testing and linkage to care. The serosurvey suggests that the same should be done for hepatitis C, where 19% of infected persons (or 1 in 5) were undiagnosed, and that testing should not only be offered to baby boomers (those born 1945-1965) but those born on either side of this range,” said author Lucia V. Torian, Ph.D., deputy director, HIV Epidemiology and Field Services, Bureau of HIV Prevention and Control for the New York City Department of Health and Mental Hygiene.