The Netherlands Drug Situation 2010 - Trimbos-instituut

The Municipal Health Service (GGD) of Amsterdam collects information on hepatitis B andC infections in methadone clients participating in low threshold services. Patients aretested exhaustive, but not every year. A selection bias in those being tested is certainlythe case, e.g., because testing is voluntary and only patients are tested with unknowntest result. The data presented for 2009 are small and have to be interpreted with caution. In 2009, HBsAg was not found in any of the 22 IDUs tested (all aged >34 years). In16 IDUs tested, 5 (31%) were positive for antiHBc. AntiHBs was found in 8 of 14tested (57%) (see also ST09). HCV antibodies were detected in 19 of 35 (54%) tested ever injecting drug users; 18of them were older than 34 years (see also ST09). The RIVM compiled data from the regular infectious disease screening program in themunicipal health service in Amsterdam. 2,566 drug users were registered in methadonecare at the municipal health service between 2004 and 2008 (Schreuder et al.,submitted).o Between 2006 and 2008, 34% (680/2024) drug users were screened for HBV. Antibodiesagainst HBV (anti-HBc) were found in 225 of 680 screened drug users(33%). The estimated vaccination coverage (full or partial vaccination) among drugusers in Amsterdam from 2006-2008 however was 92%.o Between 2004 and 2008, 53% (1359/2566) drug users were screened for HCV. Antibodiesagainst HCV were found in 350 of 1359 screened drug users (26%). In2008, 53 (15%) of those with an HCV infection started treatment.Also historical data from the addiction care in Heerlen were compiled by the RIVM: 287 drug users were in care from 2003-2008 (Schreuder et al., submitted).o In this period, 69% (197/287) of drug users were screened for HBV and 93 (48%)were anti-HBc positive, while 45% (130/287) completed a vaccination course forhepatitis B.o 66% (190/287) were screened for HCV and 115 (61%) persons had a positive testresult. Of these, 55 (48%) have started treatment. The higher prevalence of (HIV), hepatitis B and C in Heerlen compared to Amsterdammay be explained by the ongoing higher level of injecting drug use and related riskbehaviours, combined with an influx of drug users from adjacent countries. However,the data presented are cumulative over a couple of years and the collection period inHeerlen is longer, which may also contribute to the higher prevalence levels.The open and ongoing Amsterdam Cohort Studies (ACS) among drug users (see above)focuses among others on hepatitis C. The study generates a wealth of information, whichis also described in the previous National Reports. In 2009, data of the Amsterdam Cohort Studies and the Academic Medical CentreAmsterdam (AMC) were used to study the spread of HCV genotype 4 (HCV-4) in theNetherlands by using a molecular epidemiological approach (De Bruijne et al., 2009).The study population consisted of 133 patients infected with HCV-4, of whom injectingdrug use was the predominant underlying risk factor in 32%. Two subtypes, HCV-4a and HCV-4d, accounted for 93% of the infections. Evolutionary analysis of theHCV-4d infections in Amsterdam indicated that HCV-4d entered the European populationof IDUs around 1954 and spread effectively in the Amsterdam area since the sixties,thereby following a similar pattern as the HCV-1a and HCV-3a genotypes, whichare traditionally associated with IDU. Only 3 of 42 splits in the phylogenetic tree oc-86