Drug-related infectious diseases

Overview of the data | Tables | Graphics | Supplementary downloadable tables | Methods and definitions

Overview of the data

The links above give access to the tables in the bulletin, the supplementary downloadable tables and the associated graphics in the section dealing with drug-related infectious diseases, as well as to a description of the methods and definitions used in compiling this data. A brief, summary overview is provided below. See also the side navigation bar for links to all chapters.

Tables INF-1 to INF-3 are summary tables by country of the latest results held at EMCDDA, for prevalence of HIV, HCV and HBV infections among injecting drug users, showing the numbers of tests made and the percentage infected, the broader aspects of the study setting, and references to the original reports listed in the section's bibliography, Tables INF-0 part (i) and INF-0 part (ii)

In the supplementary tables, tables INF-4 to INF-6 report information on newly diagnosed or notified HIV, HCV and HBV cases respectively, giving medium-term historical data on the number of reported cases. Table INF-4 gives additionally the rate per million population for HIV infection and tables INF-5 and INF-6 give the IDU percentage among the cases that have information on the presumed transmission category

A small number of countries report incidence data for HCV from follow-up studies of IDUs at a city level. Table INF-7 reports the number of IDUs followed, the number of sero-conversions, follow-up time, the incidence rate per 100 person-years and a reference to the source study in the section's bibliography, Table INF-0 part (i).

Fuller information on which the summaries above are based as well as prevalence rates among younger injectors and new injectors can be found among the supplementary downloadable tables: Table INF-8 to Table INF-10 for HIV; Table INF-11 to Table INF-13 for HCV; and Tables INF-14 and Table INF-15 for HBV current infection prevalence and HBV antibodies prevalence, respectively.

Summary points

AIDS and HIV infection

AIDS incidence rates among IDUs are available for all EU members and show strong declines in the ‘old’ EU member countries, although there are increases in some of the ‘newer’ members.
The decline in AIDS incidence in the late 1990s is generally thought to be not only the result of reduced transmission, but also due to the introduction in 1996 of highly active antiretroviral treatments (HAART) that delay or prevent the development of AIDS. Estimates of the coverage of highly active antiretroviral treatment made by WHO-Euro suggest that in the EU and most of Central Europe over 75 % of persons in need of treatment have access to HAART. However in most countries of Eastern Europe and in the Baltic states coverage is estimated to be at best ‘poor’. Coverage estimates specific to IDUs are not available, but studies show that IDUs are often at higher risk for inadequate access to HAART than people infected by other routes. Reference: WHO Regional Office for Europe Health for all database, www.euro.who.int/hfadb (accessed 8 March 2005) (Figure INF-24, Figure INF-25).
A lack of decline or a late decline among IDUs can indicate a lack of coverage or late introduction of these treatments for IDUs or continued high transmission of HIV among IDUs.
Aids incidence in IDUs in affected countries peaked in the early 1990s: in some countries somewhat later. Few countries have evidence of recently increasing AIDS incidence for IDUs.
AIDS incidence data show that IDUs have been the most important transmission group for HIV and AIDS until 2002, when AIDS incidence due to heterosexual transmission became the largest category (Figure INF-1, Figure INF-2).
Rates in the general population of newly diagnosed HIV cases who are IDUs have strongly increased in the Baltic states, but have remained low in other EU countries.
Data on newly diagnosed cases of HIV infection shows high peaks of HIV transmission as recently as 2001 in some EU Member States and elsewhere in Eastern Europe, (see Annual report 2005, HIV/AIDS in the EU and Eastern Europe).
Some of the highest rates of newly diagnosed cases, reaching peak rates of 108 cases per 100000, were recorded in 2001.
While in the ‘old’ EU members rates have stayed constant at about 5 cases per 100000 per year (although this is likely an underestimation as data are not available from the most affected countries) rates in the five Central Asian Republics have recently increased to a similar level (Figure INF-11).
Seroprevalence data are an important complementary source of information to HIV case reports. HIV seroprevalence data, mostly from studies of IDUs in drug treatment, suggests that long-term the prevalence of HIV among IDUs has decreased in the most affected countries but has in most cases stabilised since the mid-1990s.
Since 1997/8 however some new increases are seen in the available national level seroprevalence data.
In 2002 and 2003, the HIV prevalence among IDUs shows wide variation in regional studies both within and between countries, ranging from 0 % in some of the newer members to a high of over 30 %, with several studies reporting prevalence in excess of 20 %. Recent local data are though not available from some of the most affected countries and areas.
Some very small-scale local studies among young IDUs (aged <25) and new injectors (injecting less than 2 years) found high prevalence of HIV infection (greater than 20 %), suggesting recent transmission of HIV. Data for young or new injectors also, though, is lacking from several countries and regions which have a high prevalence overall, making it more difficult to evaluate the extent of recent transmission (Figure INF-3, Figure INF-4, Figure INF-5).

Hepatitis B and C infections

HCV prevalence among IDUs (mostly among IDUs in drug treatment) is in general extremely high but shows wide variation within and between countries, ranging from 10% in some national data to 97 % in one regional study.
National data are missing for many countries and in others data relate to problem drug users, not restricted to injectors, and may thus underestimate prevalence among IDUs. Even so, data for 2001 to 2003 show high prevalence in several national samples.
Data on local/regional HCV prevalence levels are also unavailable for several countries, but high regional or local prevalence levels (exceeding 60 %) among IDUs have been found for 2001 to 2003 in studies in some countries. Lower prevalence (less than 40 %) has also been found in national and local samples in other countries.
HCV prevalence data from young IDUs (aged <25) are available from few countries only, with levels in excess of 40 % in some studies and less than 20 % in others.
Availability of data on prevalence in new injectors (injecting < 2 years) is very limited, but similar high levels are found, with the lowest levels falling below 10 % in a few countries.
The sparse trend data that are available suggest stable prevalence over time in those countries that provided data, with some exceptions (Figure INF-6, Figure INF-7, Figure INF-8, Figure INF-17).
The prevalence of HBsAg, the marker for current infection with HBV, among IDUs (mostly in drug treatment) shows similar wide variation, ranging from 0 % in one country’s local sample to 8 % in another’s national sample. This may relate to variation in the combined effect of risk behaviours among IDUs (sexual risk and needle sharing) and of (lack of) vaccination against HBV.
The highest prevalence rates are in excess of 5 % whilst some countries have less than 2 % prevalence. However as few countries are providing data on HBsAg the picture is far from complete.
Some countries show high values of antibodies for HCV and HBV but relatively low prevalence of HBsAg, which might be attributed to the effect of recently introduced vaccination against HBV.
The prevalence of specific antibodies against HBV (especially anti-HBc), which indicate a history of infection, also varies strongly within and between countries. Several countries, both old and new, have sample studies showing relatively low rates of less than 20 %, but at the same time more than 60 % prevalence is found in local samples in some countries. The prevalence of antibodies against HBV appears to vary more than the prevalence of HCV, both within and between countries.
Some countries show consistently low prevalence of antibodies against both HBV and HIV, two infections that are transmitted sexually. This might suggest that in those countries sexual risk behaviour among IDUs could be relatively low.
Some countries show consistently high figures across HIV, HCV and HBV, both in the total samples and in young and new IDUs, suggesting current transmission of these infections among injecting drug users.
Trends data for HBsAg are only available from five countries, and these show mixed results
Trends in HBV antibody prevalence show varying changes over time, with some minor increases and falls in recent years. There were declines in the first half of the 1990s in Italy and UK while Portugal shows a decline in the second half of the 1990s (Figure INF-9, Figure INF-10, Figure INF-18, Figure INF-19).
Data on the notification of hepatitis are not reliably comparable indicators across countries, due to differences in case definitions and high proportions of asymptomatic cases that are not notified. The proportion of IDUs among notification data, however, may give a comparable indication of the relative importance of drug injecting as a transmission category for both HCV and HBV.
Absolute numbers of IDU related hepatitis C notifications show a variety of trends with no consistent patterns discernable.
In the countries that provided data, the HCV notifications for 1992 to 2003 suggest that the large majority of new cases of hepatitis C (mostly considering acute cases only) are IDUs.
Proportions of IDUs among notified cases of hepatitis C vary from about 50 % in some countries to over 75 % in most others. Where trends in numbers are sufficient to permit a percentage interpretation, they do in the main show some slight decrease (Figure INF-12, Figure INF-13, Table INF-5 part (i)).
Hepatitis B notification data 1992 to 2003 for the countries with data available suggests that the proportion of IDUs has been increasing during the 1990s.
Absolute numbers of cases of IDU-related hepatitis B show strong variations in trends. Even the countries with past increases tend to show more recently declines in the past three to four years, both in absolute numbers and in percentage terms (Figure INF-14, Figure INF-15, Table INF-6 part (i)).