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

Abstract

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

Objectives: 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.

Methods: 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.

Results: 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).

Conclusions: Injecting cocaine is a new trend of drug use in Luxembourg associated with HIV infection in this recent outbreak among PWID.

Fig 1. Number of HIV-infected patients newly enrolled at the “Service National des Maladies Infectieuses” by year from 1983 to 2017 according to risk group.

MSM, Men who have Sex with Men. PWID, People Who Inject Drugs.

Fig 2. Phylogenetic trees of the two PWID HIV-1 subtype B and CRF14_BG clusters from Luxembourg related to sequences from other countries.

A. Phylogenetic tree of the PWID HIV-1 subtype B cluster. This cluster of 52 sequences from Luxembourg are related to sequences from Luxembourg, Italy and Spain. * SH value ≥ 0.95. All other SH values in the cluster were above 0.8. Diamonds represent the node of a sequence in the tree. B. Phylogenetic tree of the PWID HIV-1 CRF14_BG cluster of 10 sequences. This cluster of 10 sequences from Luxembourg are closely related to sequences from Spain and Portugal. * SH value ≥ 0.95. All other SH values in the cluster were above 0.76. Diamonds represent the node of a sequence in the tree.