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Expert Critique
FROM THE ASCO Reading Room
Along with the rise of hepatitis C infection rates among young adults is an unsettling increase in the rates of infection among teens. And studies show that the increase in this population goes hand-in-hand with increases in injection drug use resulting from the opioid crisis.
But the rates of HCV infection may be underestimated, screening is not common in this population, and treatment protocols are only just starting to catch up with that of adults.
The prevalence of HCV infection in children and adolescents has been reported to vary from 0.05% to 0.36% in the United States and Europe, to 1.8% to 5.8% in some developing countries -- and even that might be low.
According to a review published in Hepatology Communications, the six genotypes seen in adults have been identified in children, with similar global geographic distribution as adults -- but that like adults, the younger cohort in the U.S. tend to have genotypes 1 through 3.
The paper notes that while HCV infection in younger children tends to be from vertical transmission from HCV-infected mothers, in adolescents it is increasingly linked to intravenous drug abuse. In fact, one study from the Centers for Disease Control and Prevention shows a 364% increase in HCV infection among people ages 12 to 29 living in the Appalachian region of the U.S. between the years 2006 to 2012.
Other routes of infection, the review authors noted, include receiving tattoos in an unregulated setting, intranasal cocaine use, and engaging in sexual practices that involve multiple partners and/or sexual activity with trauma.
A recent study in The Journal of Pediatrics by researchers from the University of North Carolina (UNC) found that injection drug use is an increasing cause of HCV infection in adolescents nationally. The study examined patterns of children hospitalized for HCV infection from 2006 to 2012. Currently there are about 50,000 children living with chronic HCV in the U.S., the study noted.
Using the Kids' Inpatient Database, an Agency for Healthcare Research & Quality resource that contains hospital-stay information for children ages 20 and younger from over 4,100 hospitals across the country, the researchers found that nationally, the number of hospitalizations for children infected with HCV increased by 37%. Most of these patients were adolescents, of whom one-third also had a substance use disorder.
The study also found that the rates of adolescents with HCV were highest in the Northeast part of the U.S., followed by several Appalachian states, including West Virginia, Kentucky, Tennessee, and Pennsylvania -- results that reflect what has been described in adults.
"The current epidemic of new HCV cases has not spared children, and in particular, adolescents. These results also likely represent a significant underestimate of the true burden, because children would likely not manifest symptoms from HCV and would not require hospitalization. The increase in the number of hospitalized children with HCV likely represents a true increase in disease prevalence," the authors wrote.
In addition, the hospitalizations appeared to be triggered by a need for substance abuse treatment rather than for HCV symptoms. As well, girls were more likely to present with substance abuse and HCV infection -- concerning because many are of child-bearing age themselves.
According to an epidemiologic study looking at HCV patterns in Massachusetts, HCV infection rates among adolescents and young adults (ages 15-24) in the state have been going up in recent years. Data for teens are combined with data for young adults.
But in the "15 to 29 cohort, there has been a steadily increasing number of cases that has stabilized in recent years at a very high level -- approximately 2,200 to 2,300 newly reported cases annually," said Daniel Church, MPH, from the Massachusetts Department of Public Health.
However, overall, "we actually don't see a high number of teenagers being reported with HCV infection. Most of the cases in the 15-29 years age cohort are in people over the age of 18 years," he told MedPage Today. This young cohort reflect the second highest HCV rate for all age cohorts.
Injection drug use in this population is quite high, and the way to combat HCV is to combat that issue," he told MedPage Today. "Things that can help include strategies such as preventing opioid addiction, introducing safer injection practices, risk-reduction strategies, and opioid-replacement therapies.
"Physicians should also be alert to significant changes in a teenager's mood, school performance, socialization, hygiene, and overall health as signals of possible substance involvement and be prepared to conduct a structured assessment of their risk."
As for treating HCV-infected teens, some direct-acting agents (DAAs) are now approved for use in adolescents without cirrhosis or with compensated cirrhosis, with published cure rates of 98%. The American Association for the Study of Liver Diseases and Infectious Diseases Society of America Guidance includes details for testing and treatment of HCV in both children and adolescents.
But the UNC researchers said that treating HCV isn't enough in the teen population: "Unless all facets of the population are treated, even DAAs with 100% cure rate will not curb the spread of HCV ... adolescents need to be considered and included in public health efforts to address HCV in the population, and these efforts should be well integrated with substance abuse treatment programs."