Minimal transmission of HIV despite persistently high transmission of hepatitis C virus in a Swedish needle exchange program

Abstract

The aim of this study was to examine the prevalence and incidence of HIV and hepatitis B and C (HBV and HCV) among injecting drug users in a Swedish needle exchange programme (NEP) and to identify risk factors for blood-borne transmission. A series of serum samples from NEP participants enrolled from 1997 to 2005 were tested for markers of HIV, HBV and HCV (including retrospective testing for HCV RNA in the last anti-HCV-negative sample from each anti-HCV seroconverter). Prevalence and incidence were correlated with self-reported baseline characteristics. Among 831 participants available for follow-up, one was HIV positive at baseline and two seroconverted to anti-HIV during the follow-up of 2433 HIV-negative person-years [incidence 0.08 per 100 person-years at risk (pyr); compared to 0.0 in a previous assessment of the same NEP covering 1990-1993]. The corresponding values for HBV were 3.4/100 pyr (1990-1993: 11.7) and for HCV 38.3/100 pyr (1990-1993: 27.3). HCV seroconversions occurred mostly during the first year after NEP enrolment. Of the 332 cases testing anti-HCV negative at enrolment, 37 were positive for HCV RNA in the same baseline sample (adjusted HCV incidence 31.5/100 pyr). HCV seroconversion during follow-up was significantly associated with mixed injection use of amphetamine and heroin, and a history of incarceration at baseline. In this NEP setting, HIV prevalence and incidence remained low and HBV incidence declined because of vaccination, but transmission of HCV was persistently high. HCV RNA testing in anti-HCV-negative NEP participants led to more accurate identification of timepoints for transmission.

Mortality, Causes of Death and Risk Factors for Death Among Primary Amphetamine Users in the Swedish Criminal Justice System

“…While blood-borne viral hepatitis is common in the present study, less than 1% of the whole cohort reported to be HIV positive (Hakansson et al, 2008). This low prevalence of HIV is in accordance with HIV being less prevalent in injection drug users in the Swedish setting, compared to many other countries (Blomé et al, 2011), and results on causes of deaths should be seen in that perspective.…”

Hepatitis C Viremia Patterns in Incident Hepatitis C Infection and One Year Later in 150 Prospectively Tested Persons Who Inject Drugs

“…Even for subjects with access to a NEP, continuing injection drug use poses repeated risks of exposure to HCV, as both the previously observed incidence data from the Malmö NEP and other reports indicate [25], [32], [33]. Another recent longitudinal study among young PWID with ongoing risk behaviour found that several subjects with signs of spontaneous viral clearance had subsequent detectable viremia with the original viral strain (suggesting recurrence rather than reinfection) [34].…”

“…In a recent study, we reported the incidence of HIV, HBV and HCV among new participants, registered in the NEP from 1997 throughout 2005 [25]. In summary, HIV prevalence and incidence was low (baseline prevalence 0.12% and incidence 0.08/100 person years at risk [pyr] among 831 subjects), whereas previous exposure to HBV was found among 28% (linked with a HBV incidence of 3.4/100 pyr).…”

Attitudes towards Hepatitis C and Treatment Willingness in Injection Drug Users: A Follow-up Interview Study

“…More than 4,500 persons have enrolled since the start, and around 75% of participants are male. Prerequisites for enrolment in the NEP are self-reported injection drug use, age ≥ 20 years, signs of recent venepuncture, and consent to HIV testing [7]. The injected drugs in Sweden are mainly amphetamine and heroin, and among the population at Malmö NEP amphetamine is traditionally the most common main drug, followed by heroin [24].…”

“…At the needle exchange program (NEP) in Malmö, 91% tested positive for HCV [1990][1991][1992][1993], and in the same study HCV infection kept spreading despite free access to clean injection tools. The prevalence 1997-2005 at the same NEP was 60% [7]. The HCV incidence at Malmö NEP has recently been decreasing; however, the prevalence is still high.…”