Hepatitis C virus (HCV) infection and resulting liver disease is most prevalent among baby boomers, but a recent study found evidence that the number of infected adolescents and young adults may be rising in the U.S., according to a report in the May 6, 2011, Morbidity and Mortality Weekly Report.

Researchers with the Massachusetts Department of Public Health (MDPH) and the Centers for Disease Control and Prevention (CDC) described findings from a Massachusetts surveillance initiative to collect more detailed information about hepatitis C cases reported during 2007-2009 among people in the 15-24 year age group.

Nationwide, rates of symptomatic acute HCV infection declined during 1992-2005 and then began to level off, the study authors noted as background. Rates of newly reported HCV infection in Massachusetts also declined overall during 2002-2006, but an increase was seen in the 15-24 age group.

Results

	The surveillance initiative revealed continued increases in newly reported HCV infections among people age 15-24 years.
	During 2002-2009, the rate of newly reported confirmed and probable HCV infections in this group increased from 65 to 113 cases per 100,000 people.
	During 2007-2009, MDPH received 1925 reports of new HCV infections among people age 15-24 years, of which 1026 (53%) were confirmed.
	Most newly reported infections (78%) occurred among non-Hispanic whites, and were distributed equally between men and women.
	New cases were reported from all areas of the state, including large metropolitan areas, suburbs of Boston, smaller cities, and rural areas.
	8% of new infections with complete case report forms occurred among homeless or incarcerated people.
	Current or past injection drug use was the most common HCV transmission risk factor, reported by 72%.
	Among injection drug users, 85% reported heroin use, 29% cocaine use, 1% methamphetamine use, and 4% other drugs (some used more than 1 drug).
	34% of newly infected people reported a history of nasal drug use, but most of them also reported injecting drugs, making the transmission route uncertain.

Rates of newly reported cases of hepatitis C virus infection (confirmed and probable) among persons aged 15--24 years and among all other age groups --- Massachusetts, 2002--2009

"The increase in case reports appears to represent an epidemic of HCV infection related to [injection drug use] among new populations of adolescents and young adults in Massachusetts," the researchers concluded. "The findings indicate the need for enhanced surveillance of HCV infection and intensified hepatitis C prevention efforts targeting adolescents and young adults."

"Although calculating an incidence rate from the surveillance data or determining the duration of infection for persons who tested positive for anti-HCV antibody is not possible, the findings suggest that most persons aged 15-24 years with HCV infection likely acquired their infections within a few years of being tested and reported," wrote the authors of an editorial note accompanying the report.

During this period of increasing HCV infection, Massachusetts also experienced a corresponding increase in heroin use among adolescents and young adults (based on records from substance abuse programs), while the rate of reported injection drug use among other age groups remained relatively constant

"Although similar increases in [HIV] infection were not identified for this age group, increases in reports of HCV infection among injection drug users might be a harbinger of increases in IDU-associated HIV," they added. HCV is more easily transmitted than HIV, and infection with the former typically occurs sooner after a person starts injecting drugs.

This report "strongly indicates the need for expanded and intensified hepatitis C prevention efforts targeting adolescents and young adults," the editorial authors concluded. "Some interventions that could be implemented include access to sterile syringes and drug preparation equipment through syringe exchange services, expanded school-based education that includes viral hepatitis prevention messages, expanded harm reduction programs directed toward young drug users, entry to drug treatment for young injection drug users, and access to comprehensive health services that include HCV testing and linkage to care."

Investigator affiliations: Massachusetts Dept. of Public Health, Boston, MA; Division of Viral Hepatitis, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, CDC, Atlanta, GA.

5/13/11

Reference
S Onofrey, D Church, P Kludt, et al. Hepatitis C virus infection among adolescents and young adults -- Massachusetts, 2002--2009. Morbidity and Mortality Weekly Report 60(17):537-541 (free full text). May 6, 2011.