Epidemiology of drug use and Hepatitis C in New York City (and beyond)

1. Epidemiology of drug use and Hepatitis C in New York City(and beyond) Holly Hagan, PhD Director, Research Methods Core Center for Drug Use and HIV Research National Development and Research Institutes New York

2. What factors affect transmission of an infectious disease in a population? Host Environment Virus

3. Factors favoring rapid spread of HCV • Host: • High proportion of IDUs who share injection equipment • Lack of knowledge • Fatalism • Environment: • Large number of infectious carriers capable of transmitting infection to others • A lot of infectious material in injection settings • Virus: • Efficiency of HCV transmission

4. Risk Factors for HCV

5. Injection risk behavior - US IDUs

6. Prevalence Ina sample of 50 IDUs, 25 are anti-HCV positive Prevalence = 25/50 or 50% = anti-HCV+ = anti-HCV-

7. 63% 69% 78% 88% 33-62% 52% 74% 90% 80% 80% 66% 85% 82% 80% 54% 98% 80% 63% 64% 45% 67% 67% 84% Anti-HCV Prevalence in IDUs around the world

8. Prevalence of HCV & HIV in IDUs

9. Anti-HCV prevalence in young or new injectors

10. Enrollment 1 year later HCV Incidence 25 anti-HCV negative IDUs followed for 1 year 5 become anti-HCV positive HCV Incidence=5/25, or 20%

11. Person-years: Person Years 1 A 1 B 1 C 1 D ½ E 12 months 6 months 0 4 ½ Time in the study

12. Incidence of HCV & HIV in IDUs

13. HCV incidence in young or new injectors

14. Time to HCV seroconversion in a cohort of Seattle IDUs Hagan H, Thiede H, & Des Jarlais DC. Epidemiology, 2004.

15. Time to HCV seroconversion • Purpose • Estimate the length of the opportunity to prevent HCV infection in IDUs • 484 HCV-negative Seattle IDUs followed to observe HCV seroconversion • Average follow-up 2.1 years • Range 0.4 – 7.5 years • 1153 person-years of observation • 134 HCV seroconversions • 11.6/100 person years (all subjects) • 15.4/100 person-years (current injectors)

16. Kaplan-Meier plot of HCV seroconversion in Seattle IDUs

17. Average time to HCV seroconversion from first injection Used seroincidence and seroprevalence data from 383 new injectors (injecting < 2 years) • 41% of new injectors were anti-HCV positive at enrollment • Midpoint between 1st injection and enrollment was used to estimate time to HCV infection • Anti-HCV negative new injectors were followed up • Observed time to HCV infection from 1st injection Used these estimates to calculate a weighted time to seroconversion, using this formula: (41% X time to HCV infection) + (59% X mean time to HCV infection)

18. Estimated time to HCV seroconversion in new injectors • HCV-positive new injectors: • Midpoint between 1st injection and study enrollment 0.6 years • HCV-negative new injectors • Mean time to HCV seroconversion was 5.4 years • Weighted average time to HCV seroconversion • (41% X 0.6 yrs) + (59% X 5.4 yrs) = 3.4 years

19. Odds ratios & relative risks(OR, RR) Evaluates risk of disease related to • Risk factor • Participation in a prevention program Example: Studies of HCV incidence in IDUs

20. Methadone and HCV prevention

21. Needle exchange & HCV prevention

22. Disinfectant bleach & HCV

23. Risk Factors Study,New York City 1984-present • Subjects recruited from drug detoxification program at Beth Israel Medical Center • City-wide program, approximately 7000 patients per year • Approximately 300 subjects recruited into the study each year, 1990 to 2001 • Structured interview, HIV, and (limited) HCV testing • DC Des Jarlais, PI • Funded by NIDA, CDC, WHO

25. HIV Prevalence NYC IDUS, 1990-2001 Source: DC Des Jarlais et al

26. Recent HIV Incidence StudiesNew York City IDUs • 13 separate studies • Range from 0 to 3/100 person-years • Weighted average > 1/100 person years

27. HCV SeroprevalenceNYC IDUs Source: DC Des Jarlais et al

28. HIV Seroprevalence NYC IDUs, 2002 Source: DC Des Jarlais et al

29. HCV Seroprevalence NYC IDUs 2000-01 Source: DC Des Jarlais et al

30. Recent HCV Incidence StudiesNew York City IDUs • 3 studies • C. Harlem, Lower East Side, E. Harlem • Incidence from 10 to 33/100 person years

31. HCV Seroprevalence in New Injectors, New York City Source: DC Des Jarlais et al

32. Trends in Hepatitis C PrevalenceIn Seattle IDU1994-2003 Burt R, Thiede H, Garfein R, Sabin K,& Hagan H. Manuscript under review, 2005

33. Seattle Studies of IDUs 18 - 30 years old1994 - 2003 • RAVEN I • 1994 - 1997 • Methadone treatment centers, SOS, ADATSA, de-tox, Jail • RAVEN II • 1998 - 2000 • Similar to RAVEN I • Kiwi • 1998 - 2002 • City jail • DUIT • 2002 - 2003 • Street outreach and respondent driven sampling

36. Limitations • Every study has limitations (bias) that can affect the results • Prevalence and incidence can vary greatly in relation to where and how the sample is selected • May be very difficult to show that prevention works • Community-level effects are difficult to study • Prevention programs like needle exchange tend to target high risk injectors

37. Summary • HCV easily transmitted and difficult to prevent! • Can’t apply what we know about HIV prevention to HCV and expect the same results • However, variation in prevalence and incidence indicates that there are cases where HCV spreads more slowly • Prevalence between 30 - 90% • Time to HCV seroconversion 1.5 - 3.5 years • This is logical, because not all IDUs are alike and not all injection settings are alike • We need to study this variation, to understand how we can alter behavior, beliefs and settings to reduce HCV transmission

38. Acknowledgements Don Des Jarlais, Hanne Thiede, and Richard Burt provided data from their studies and contributed to many of the ideas in this presentation Support for studies by NIDA, CDC, AmFAR