Hepatitis C virus (HCV) continues to be the number one cause of cirrhosis and liver cancer and the primary indicator for liver transplantation in the United States, yet it remains vastly underdiagnosed.

More than three million people in the U.S. are infected. Guidelines support widespread screening for HCV, and excellent treatments are now available.

So the question remains: Why is HCV underreported?

When “good” news disguises bad

A recently published study found that, according to the National Health and Nutrition Examination Survey (NHANES), the estimated prevalence of chronic HCV infection has decreased from 1.3 percent of the population (3.2 million persons) to 1.0 percent (2.7 million persons).

That would seem like a sign of notable progress. But the study has important limitations.

One major limitation of this estimate is that it excludes the homeless and people who are incarcerated. In a recently published systemic review and meta-analysis in Hepatology, approximately 668,500 prisoners and others in enclosed environments in North America were projected to be HCV antibody positive. That’s 24 percent of the entire North American prison population.

While the study in question focused on the United States, it’s useful to look at global trends. According to the Global Burden of Diseases, Injuries and Risk Factors 2010 Study, the prevalence of HCV rose from 2.3 to 2.8 percent globally (>122 million to >185 million) between 1990 and 2005.

The NHANES findings also suggest that the decrease in disease prevalence appears to be related to an increase in HCV-related deaths rather than to cured infections. Since 2006, deaths related to HCV have outnumbered those from HIV infection, according to an analysis by the Centers for Disease Control (CDC). Several studies have shown a marked increase in the number of HCV-associated hospitalizations and deaths over the past decade, and most experts suspect that this is a gross underestimate.

While the CDC estimates that from 2.7 to 3.9 million people in the United States are chronically infected with HCV, most remain unaware that they are infected. I’ve seen this firsthand, as many newly diagnosed patients who present with advanced liver disease say “My liver tests were always normal.” Patients who are chronically infected are frequently asymptomatic, with normal or only mildly elevated liver enzymes.

Chronic HCV infection is an indolent infection (meaning it’s slow to develop) that causes ongoing inflammation and scarring in the liver, with complications from chronic infection, including cirrhosis and liver cancer, appearing after several decades of living with the virus.

More rigorous HCV testing needed

More effective and rigorous screening with HCV antibody testing is necessary to identify asymptomatic individuals. The CDC published guidelines for screening in 1998, recommending that doctors test individuals for HCV if they have used intravenous drugs, have certain medical conditions or received a blood transfusion or transplant before 1992. Subgroups of the population with a high prevalence of HCV infection include HIV-positive people, Vietnam-era veterans, incarcerated persons and black males ages 40 to 49, with prevalence rates ranging from 11 to 15 percent.

Almost half of people with positive HCV antibodies had no known exposure risk, and it has become clear that risk-based approaches are not adequate to identify infected persons in the general population.

In 2012, the screening guidelines were updated to include all adults born between 1945 and 1965, as people born during this time period accounted for up to 75 percent of all chronic HCV infections. In 2013, the U.S. Preventive Services Task Force took note of the CDC’s recommendations and updated its screening guidelines to reinforce the importance of screening for viral hepatitis; its “grade B” recommendation means there is either high certainty that the benefits of such screening are moderate or a moderate certainty that the benefits are moderate to substantial.

This is not enough, though. In a busy primary-care practice, screening for HCV infection often falls by the wayside as doctors manage diabetes and heart disease. In one study, only 36 percent of physicians adhered to the screening guidelines. Outreach efforts are needed to educate patients and physicians regarding the value of early identification of HCV infection and referral for treatment.

More effective drugs can mean cure

The landscape of HCV treatment has changed dramatically. For years, patients and physicians struggled to cure the virus with interferon-based therapies that were difficult to tolerate and successful in only 15 to 40 percent of patients. Recent advances in research have given us an understanding of HCV replication, which has led to the development of direct-acting antiviral agents. These medications (two of which, sofosbuvir and simeprevir, were approved by the Food and Drug Administration in late 2013, with many more in the clinical-trial pipeline) have made it possible to treat and cure more patients with much less risk.

With the successful treatment of HCV, there is a clear reduction in all-cause mortality, cirrhosis, liver cancer and the need for liver transplants.

The high cost of this treatment is considered a barrier for some. The regimen can cost $150,000 for a three-month course of treatment, which usually includes more than one antiviral drug. Justifying that cost and exploring ways to increase access to treatment are hotly debated topics.

The burden of HCV is increasing, with an estimated 165,900 deaths from chronic liver disease and $10.7 billion in direct medical expenditures expected to occur between 2010 and 2019. Liver transplantation is a lifesaving operation for patients with advanced liver disease or liver cancer, but due to organ shortages, it remains an option only for a select few.

What I can say, as a Montefiore specialist who treats liver disease and an Einstein assistant professor who joins colleagues in researching the ravages of chronic HCV, is that we need to be aggressive about getting as many people tested as possible (within guidelines) and raising awareness about a virus that is often a silent pathogen until it’s too late.

We have the tests to diagnose HCV and the drugs to cure a high percentage of HCV cases. We should use them fully.

Kristina R. Chacko is a gastroenterologist and an assistant professor, department of medicine, Albert Einstein College of Medicine, Bronx, NY. She blogs at The Doctor’s Tablet.