Treatment of Hepatitis C as Prevention: A Modeling Case Study in Vietnam

Background: Treatment of hepatitis C (HCV) is very effective, achieving a cure in 50–90 % of patients. Besides its own good for individuals, this most likely translates in reduced transmission, but this phenomenon has yet to be fully explored. Methods and Findings: In this mathematical modeling study done in the context of Vietnam, we estimated the public health benefit that HCV therapy for injecting drug users (IDUs) may achieve. Treatment coverage of 25, 50 and 75 % of chronically HCV-infected IDUs (4 years into infection) is predicted to reduce the chronic HCV viremia prevalence respectively by 21, 37 and 50%, 11 years after full scale up to the intended coverage. At a constant 50 % coverage level, earlier treatment, 3, 2, and 1 year into infection is predicted to reduce the chronic HCV viremia prevalence by 46, 60 and 85%. In these later 3 scenarios, for every 100 treatment courses provided, a total of respectively 50, 61 and 94 new infections could be averted. These benefits were projected in the context of current low coverage of methadone maintenance therapy and needles/ syringes exchange programs, and these services expansion showed complementary preventive benefits to HCV therapy. The program treatment commitment associated with the various scenarios is deemed reasonable. Our model projections are robust under adjustment for uncertainty in the model parameter values. Conclusions: In this case study in Vietnam, we project that treatment of HCV for injecting drug users will have a preventative herd effect in addition to curing patients in need for therapy, achieving a substantial reduction in HCV transmission an

High HIV sexual risk behaviors and sexually transmitted disease prevalence among injection drug users in northern Vietnam - Implications for a generalized HIV epidemic

Background: HIV prevalence in Vietnam is currently concentrated among injection drug users (IDUs). The extent to which this core risk group represents a potential for broader HIV transmission to the general population is currently unknown. Methods: A community-based cross-sectional study among IDUs in Vietnam assessed sexually transmitted disease (STD) prevalence and behavioral risk factors. Qualitative interview data enhanced quantitative findings. Results: The prevalence of any STDs among 272 IDUs was 30% (chlamydia, 9%; herpes simplex virus type 2 [HSV-2], 22%; gonorrhea, 0%; and syphilis, 1%). Part-time work or unemployment (odds ratio [OR] = 2.74, 95% confidence interval [CI]: 1.1 to 6.9). sex with >= 2 sex workers in the past year (OR = 4.9, 95% CI: 1.91 to 12.6), having ever smoked heroin (OR = 4.5, 95% CI: 1.1 to 18.3), and injecting less frequently than daily (OR = 3.9, 95% CI: 1.43 to 10.6,) were independently associated with chamydial infection. Urban residency (OR = 4.0, 95% CI: 1.4 to 11.0) and daily injecting (OR = 2.2, 95% CI: 1.1 to 4.4) were independently associated with HSV-2. Odds of HSV-2 among older (>= 28 years of age) IDUs who had sex with < 2 sex workers in the past year was higher than among younger IDUs who had sex with more sex workers (OR = 6.4, 95% CI: 2.1 to 18.4). Conclusions: High STD prevalence and high-risk sexual and parenteral behaviors among IDUs indicate the potential for HIV STD transmission to the general Vietnamese population