Hepatitis C virus is the world’s most prevalent blood-borne viral infection for which a vaccine does not exist. To eliminate HCV infection on a global scale, experts argue that vaccine development needs to become a public health priority.
Curing the preponderance of patients treated for hepatitis C virus (HCV) is one of medicine’s most notable milestones, but research in this area appears to be grinding to a halt, according to a commentary in the first 2017 issue of Hepatology.
With HCV dominating the subspecialty of hepatology for the past 25 years, some scientists believe that research should turn its attention and monetary resources to more urgent needs.
Other experts disagree with that viewpoint. “The mission for HCV eradication is far from accomplished,” Hugo R. Rosen, MD, FACP, FAASLD, head of gastroenterology and hepatology at the University of Colorado Anschutz Medical Campus in Denver, noted in the commentary.
“HCV is cured with 12 weeks of treatment or less in more than 95% of patients,” Dr. Rosen, who is also professor of medicine, immunology and microbiology, and Waterman Chair in Liver Research, told Contagion®. “However, many patients do not even know they have HCV infection, and the majority will not have access to the newer medications.”
While unaware of their infection, they remain at risk for transmission and disease progression, including cirrhosis and liver cancer. Previous risk-based screening strategies had failed to detect more than half of all HCV infections, so a significant surge in the number of patients developing these complications is expected in the next few decades as the population ages.
In anticipation of this future epidemic, in 2012 the Centers for Disease Control and Prevention expanded screening guidelines to include a one-time HCV test to all individuals born between 1945 and 1965.
“Considering the ﬁrst step toward improving health outcomes and preventing HCV transmission is identiﬁcation of those with active infection, it seems odd to abandon research into HCV in the wake of direct-acting antivirals (DAAs),” Dr. Rosen contended in the commentary in Hepatology, a journal of the American Association for the Study of Liver Diseases (AASLD).
For patients who have failed to respond to all-oral DAA combination therapies, hope is on the horizon. Longer retreatment with the same class of drugs or the addition of the antiviral medication ribavirin may be effective in some individuals, although with decreased antiviral efﬁcacy. Currently, resistance testing is guiding the selection of the strongest retreatment possibilities.
“DAAs have revolutionized HCV treatment, but HCV will still be an important problem,” Dr. Rosen told Contagion®. Some unanswered questions require additional study despite funding uncertainty.
HCV is the world’s most prevalent blood-borne viral infection for which a vaccine does not exist. To eliminate HCV infection on a global scale, vaccine development needs to become a public health priority.
“Efforts should continue in this regard,” said Raymond T. Chung, MD, co-chair of the HCV Guidance Panel, a collaboration between AASLD and the Infectious Diseases Society of America (IDSA).
Even with the remarkable success of curative antiviral therapy, Dr. Chung, who reviewed Dr. Rosen’s article at Contagion®’s request, agreed that lingering questions beckon for answers in the HCV research field. The risk of further liver disease progression, including development of liver cancer in patients who have been cured of the virus, is the most pressing question.
“The answer has important ramifications for the monitoring of patients after cure of the infection, since many will have significant scarring that may continue to progress,” said Dr. Chung, director of hepatology at Massachusetts General Hospital and an associate professor at Harvard Medical School.
Historically, disease elimination of all previously controlled infections, including smallpox and polio, has required vaccination. For most infections, simple and effective treatment is inadequate to result in substantial control, Dr. Rosen noted in the commentary.
“Syphilis is the best example, for which a single dose of penicillin (which literally costs pennies and that we have had since 1945) is curative in early stages,” he wrote. “Not only have we not eradicated syphilis, rates of infection have increased in many places within the United States in recent years.”
Preventing HCV with vaccination would have the most impact on at-risk populations—for example, individuals who inject drugs. For more than three decades, injectable drug use has been the primary means of transmitting HCV, but other risk factors include inadvertent exposure through medical procedures, such as dialysis.
Illnesses stemming from HCV are the top cause of death among individuals who inject drugs. In this group, the incidence of HCV is 10-fold higher than HIV infection, ranging from 60% to 90%.
Advocating for a team-oriented scientific approach, Dr. Rosen stressed that transformative advances will depend on continued support and collaboration between federal and nonfederal sources.
“Clearly,” he wrote in the commentary, “innovative research is the vital component in order to move from the DAA era to the post-elimination/endgame era of HCV, a process not aided by the public declaration that the HCV ﬁeld is dead.”
Susan Kreimer, MS, is a medical journalist with more than 2 decades of experience. Her coverage has informed consumers, physicians, nurses, and health system executives. Ms. Kreimer holds a master’s degree in journalism from Columbia University and lives in New York City.