Hepatitis C

Injecting Drug Users and HCV

Prevalence of HCV infection among injecting drug users (IDUs) ranges from 50% to 95%, according to the National Institutes of Health Consensus Development Program. HCV infection usually occurs relatively soon after initiation of injecting drug use with over 50% of IDUs infected in the first year, 75% within 2 years, and over 80% 3 or more years after. Although direct sharing of syringes (i.e., multiperson use of a syringe) is the most efficient method of HCV transmission, sharing of drug preparation equipment [Page 455](e.g., spoons and cookers for mixing drugs, cotton filters, and water for dissolving drugs or rinsing syringes) may account for a sizable proportion of HCV incidence among IDUs.

Noninjecting Drug Users and HCV

Although the prevalence is much lower than among IDUs, illicit drug users that have never injected (non-IDUs) are also at increased risk for HCV infection. Estimates of HCV prevalence among non-IDUs range from 2% to 35%, according to R. Scheinmann and colleagues. Although there is debate about the mechanisms of HCV infection among non-IDUs, several mechanisms have been implicated, which include engaging in high-risk sexual practices, sharing of non-injection drug paraphernalia, and tattooing. Although HCV is not readily transmitted sexually, sexual transmission does occur. Elevated levels of HCV infection have been observed among patients seeking treatment for sexually transmitted infections (STIs), particularly those that involve genital ulcers such as syphilis, chancroid, and herpes simplex virus type 2. Stimulants such as crack cocaine, powder cocaine, and metham-phetamine have been associated with increased frequency of sex, greater numbers of sexual partners, exchanges involving sex for drugs, higher rates of STIs, and extended duration during sexual encounters, all of which may increase the risk of HCV infection. HIV infection also increases the risk of contracting HCV sexually. Non-IDUs may also increase their risk for HCV infection by sharing of paraphernalia such as straws for snorting or inhaling powder cocaine and pipes for smoking crack cocaine, particularly if they contain small amounts of blood from sores inside the nose from irritations caused by the cocaine or from burns on the lips from crack pipes.

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