Viral evolution of hepatitis C in injection drug users.

Dove L, Phung Y, Bzowej N, Kim M, Monto A, Wright TL.

Department of Veterans Affairs Medical Center and University of California, San Francisco, CA, USA.

Summary. Injection drug users represent the largest cohort of patients with established hepatitis C virus (HCV) infection as well as the group that is at highest risk for new infections. Most published studies have focused on the clinical consequences of established HCV infection and have not examined the consequences of new infection. The aim of the current study was to measure the virological consequences of HCV in patients with ongoing injection drug use that might pose a risk for new and/or for superinfection with additional strains of HCV. We examined the following groups: (a) those with resolved HCV infection with ongoing injection drug use, (b) those with chronic infection who continued to inject and (c) those with chronic infection who no longer injected. Our study demonstrated a spectrum of responses. The majority of patients appeared to be 'protected' from new infection. None of six patients with resolved infection had detectable HCV RNA by quantitative or qualitative PCR when followed for 1 year. Similarly, despite ongoing injection drug use, no patient with persistent infection had a 'switch' in HCV genotype indicative of possible superinfection. Virological analysis of HCV quasispecies to detect possible infection with new variants of HCV in patients with apparently 'stable' infection, indicated divergence of virus over time, divergence that was unrelated to injection drug behaviour. Thus, patients with ongoing or prior HCV infection appear to develop immunity that protects against further infection with HCV despite repeated exposure.

PMID: 16255758 [PubMed - in process] 

(Note: If this were the case, wouldn't this be a vaccine?) We know plenty with different geno types of Hepatitis C. We also know of some with positive tests, yet unidentifiable strains.

Research for the Indian Council of Medical Research

Sir--Research for the Indian Council of Medical Research on injecting drug users (IDUs) in Kolkata city in 1996 showed that the prevalence of HIV-1, hepatitis B, and hepatitis C was 1%, 8%, and 17%, respectively.^1,2 As a result of these findings a local community-based organisation started a needle and syringe exchange programme in Kolkata city. IDUs are given fresh syringes and needles daily by the trained outreach workers under supervision of field supervisors. This equipment is taken back from the IDUs the next day after use. IDUs are also given free condoms.

In February, 2002, we assessed IDUs and noted that the prevalence of HIV-1 infection, hepatitis B, and hepatitis C was 2%, 18%, and 66%, respectively. Weekly surveillance of IDUs was then initiated to monitor their risk behaviour and to assess the effect of Kolkata's needle and syringe exchange programme on infection among IDUs. We assessed this cohort in January, 2003, and noted that of 102 IDUs, 82 (80%) were infected with hepatitis C virus (HCV). The prevalence of HIV-1 infection and hepatitis B had not changed since 2002. Weekly surveillance data showed that of 140 IDUs, 112 (80%) injected drugs about twice a day. Most IDUs did not share their syringes and needles, only seven (5%) shared equipment with others. However, about 50% or more of our study participants shared drugs from the same ampoules.

Although IDUs are at increased risk of HCV infection,³ this continuous increase in HCV infection among IDUs, despite the needle and syringe exchange programme, is a cause for concern. The cause of this striking increase in HCV infection is unclear. One possible explanation is the risk behaviour of IDUs. Indirect drug sharing from common ampoules means that contaminated body fluid from one IDU is mixed with the drug inside the ampoule and then used by other IDUs. Transmission of HCV may also result from sharing of a small pot containing water that IDUs use to clean syringes and needles before and after injection of drugs. Another possibility could be shared use of the cotton swabs, which are provided with syringes to stop bleeding. The needle and syringe exchange programme alone is not able to control HCV transmission among IDUs in Kolkata. A culturally sensitive behavioural intervention is urgently needed to protect this IDU community from HCV infection.

*K Sarkar, S Mitra, B Bal, S Chakraborty, S K Bhattacharya

National Institute of Cholera and Enteric Diseases, Post Bag 33, CIT Road Scheme XM, Kolkata 700010, India (e-mail:kamal412496@yahoo.com)

1 Panda S, Chatterjee A, Sarkar S, et al. Injecting drug use in Calcutta: a potential for an explosive HIV epidemic.  Drug Alcohol Rev 1997; 16: 17-23. [PubMed]

2 Sarkar S. WHO Drug Injecting Study. Phase II planning meeting, Bangkok, Sept 11-15, 1995.

3 Quer J, Esteban JI. Hepatitis C virus: epidemiology. In: Zukerman AJ, Thomas HC, eds. Viral hepatitis. London: Churchill Livingstone, 1998: 271-83.