Research Article: Injection of cocaine is associated with a recent HIV outbreak in people who inject drugs in Luxembourg

Date Published: May 16, 2019

Publisher: Public Library of Science

Author(s): Vic Arendt, Laurence Guillorit, Alain Origer, Nicolas Sauvageot, Michel Vaillant, Aurélie Fischer, Henri Goedertz, Jean-Hugues François, Ivailo Alexiev, Thérèse Staub, Carole Seguin-Devaux, Georgios Κ Nikolopoulos.


An outbreak of HIV infections among people who inject drugs (PWID) started in 2014 in Luxembourg.

We conducted phylogenetic and epidemiological analyses among the PWID infected with HIV in Luxembourg or attending the supervised drug consumption facility (SDCF) to understand the main causes of the outbreak.

Between January 2013 and December 2017, analysis of medical files were performed from all PWID infected with HIV at the National Service of Infectious Diseases (NSID) providing clinical care nationwide. PWID were interviewed at NSID and SDCF using a standardized questionnaire focused on drug consumption and risk behaviours. The national drug monitoring system RELIS was consulted to determine the frequency of cocaine/heroin use. Transmission clusters were analysed by phylogenetic analyses using approximate maximum-likelihood. Univariate and multivariate logistic regression analyses were performed on epidemiological data collected at NSID and SDCF to determine risk factors associated with cocaine use.

From January 2013 to December 2017, 68 new diagnosis of HIV infection reported injecting drug use as the main risk of transmission at NSID. The proportion of female cases enrolled between 2013–2017 was higher than the proportion among cases enrolled prior to 2013. (33% vs 21%, p < 0.05). Fifty six viral sequences were obtained from the 68 PWID newly diagnosed for HIV. Two main transmission clusters were revealed: one HIV-1 subtype B cluster and one CRF14_BG cluster including 37 and 9 patients diagnosed since 2013, respectively. Interviews from 32/68 (47%) newly diagnosed PWID revealed that 12/32 (37.5%) were homeless and 27/32 (84.4%) injected cocaine. Increased cocaine injection was indeed reported by the RELIS participants from 53 to 63% in drug users with services contacts between 2012 and 2015, and from 5 to 22% in SDCF users between 2012 and 2016. Compared with PWID who injected only heroin (n = 63), PWID injecting cocaine and heroin (n = 107) were younger (mean of 38 vs 44 years, p≤0.001), reported more frequent piercing (≤0.001), shared and injected drugs more often (p≤0.01), and were more frequently HIV positive (p<0.05) at SDCF using univariate logistic regression analysis. Finally, in the multivariate analysis, use of heroin and cocaine was independently associated with younger age, piercing, sharing of drugs, and regular consumption (p<0.05). Injecting cocaine is a new trend of drug use in Luxembourg associated with HIV infection in this recent outbreak among PWID.

Partial Text

Latest estimates report around 15.6 million people who inject drugs (PWID) worldwide [1]. In Europe, newly reported cases of HIV among PWID remained stable in recent years[2]. Nevertheless, several large local outbreaks were described in Europe and, more recently, in the United States, which demanded effective scaled-up prevention responses [3–8]. These outbreaks appeared in specific conditions that foster rapid spread of the virus such as economic crisis, increased homelessness, or no access to needle/syringe exchange programs (NSP) and HIV testing [9].

Early March 2014, a higher number of 6 new HIV infections among PWID was recorded at NSID leading to a closer investigation of the new HIV cases An outreach program was further launched at the SDCF in October 2015 by clinicians of the NSID supported by research nurses of the Luxembourg Institute of Health to expand targeted HIV screening in this key population and a total of 77 PWID were referred to NSID between 2013 and 2017 (Fig 1), of which 68 PWID were newly diagnosed for HIV and 9 were previously infected with HIV in another country but not referred to NSID. Among them 21 were newly diagnosed at SDCF from October 2015 via the outreach program. Among the 68 newly diagnosed PWID cases, the median age was 36 years old (IQR 31–38), 51/68 (75%) were male, 41/68 (60%) were born in Luxembourg, 39/68 (57%) stopped school before the age of 15 years old and 54/68 (79%) were unemployed. 22/68 (32%) were diagnosed early after infection (four patients were diagnosed during the acute phase of infection and 18 seroconverted within 6 months as shown by HIV-1 western-blotting [18]) .55/68 (80%) PWID were co-infected with HCV.

Using different data sources, we confirm in the present work a recent HIV outbreak among PWID in Luxembourg mainly due to network transmission: (1) Phylogenetic analysis of sequences from all HIV-infected patients referred to NSID showed that the HIV transmission among PWID was concentrated in 2 two monophylogenetic clusters (46 of 77 PWID), (2) The RELIS database indicate the increase in cocaine supply both in drug treatment services and at SDCF, and (3) the epidemiologic analysis on drug consumption performed mainly at SDCF suggest that injecting cocaine might be a contributing factor related to HIV infection since this factor was significant in univariate analysis. Data routinely collected at SDCF showed the higher frequency of injections per day for cocaine users, leading to increased needs of sterile injection paraphernalia. Moreover, it is tempting to speculate that the introduction of cocaine injection contributed to a major change in psychosocial behavior challenging existing prevention measures against HIV infection. Our data suggest indeed that most of the newly diagnosed patients had knowledge on HIV transmission and prevention by attending NSP/OST facilities and being tested previously for HIV.

A recent HIV outbreak was observed in PWID injecting cocaine, living in precarious situation in Luxembourg. Prevention offers including HIV testing have been reinforced in harm reduction facilities, outreach offers and SDCF. This might have contributed to some extend to the higher number of detected cases in 2015 and 2016. 56/68 PWID (82%) were under antiretroviral treatment and 50/68 (73%) had an undetectable viral load in december 2017; early access to antiretroviral therapy being actively used as a prevention measure to contain the outbreak. Outreach offers targeting injectors and marginalised drug users were further developped. Preexposure prophylaxis in active PWID might also be considered as an additional tool in the near future [24], especially for women and cocaine injectors for which no substitution therapy exists. Ultimately, the recurring of HIV infection in PWID in the recent years emphasises the added value of continuous drug monitoring systems in the detection of emerging drug use patterns. Early indicators of behaviour’s changes among drug users need to be recorded for the elaboration of fast and targeted responses.