EMCDDA logo Annual report on the state of the drugs problem in the European Union 2001

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Introduction to the annual report
Chapter 1: Drug demand and drug supply
Chapter 2: Responses to drug use
Chapter 3: Selected issues
Cocaine and 
base/crack cocaine
Infectious diseases 
Synthetic drugs 
Chapter 4: The drugs problem in central and eastern European countries
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CHAPTER 3

Infectious diseases

Infectious diseases: Prevalence and trends | Determinants and consequences, harm-reduction responses,

 

Prevalence and trends

HIV
The prevalence of HIV infection differs much between countries - and within countries, between regions and cities. Although divergent sources and data-collection methods make comparisons difficult, available data indicate average levels of infection among different subgroups of injecting drug users (IDUs) that roughly vary from about 1 % in the United Kingdom to 32 % in Spain (see Figure 8, Chapter 1).

HIV prevalence seems to have stabilised in most countries since the mid-1990s after the sharp declines that followed the first major epidemic among IDUs in the 1980s (see Figure 24). In some countries (Austria, Luxembourg, Ireland, the Netherlands, Portugal and Finland) transmission may again be increasing among subgroups of IDUs (See box on possible increases in HIV transmission..., Chapter 1).

Figure 24

Fig.24
Sources

National focal points. For primary sources see complementary statistical table.

Figure 25

Fig.25
 

NB

Data for Ireland are positive HIV tests in IDUs.
Sources

National focal points. See also statistical table.

Recent transmission may be clearer if one looks specifically at prevalence in IDUs aged less than 25. HIV infections in this group must have occurred on average more recently, as most IDUs start injecting at between the ages of 16 and 20 (1, 2).

The trends in this age group, as far as data are available, are more marked than general prevalence and sometimes even in the opposite direction. In Finland, for instance, a large outbreak occurred in 1998-99, as can be seen from HIV notifications data (Figure 25). After 1999, overall prevalence declined, as indicated by data from needle exchanges (Figure 24); however, prevalence in young IDUs increased from 0 % in 1999 to about 4 % in 2000. This might indicate that once new infections among older injectors began to decline due to saturation (most persons at risk have become infected) and/or behaviour change of those at risk, new infections mainly took place among younger injectors, who often have higher levels of risk behaviour.

In several countries, HIV prevalence is consistently higher in female IDUs than in male IDUs. This may be due to higher levels or different ways of needle sharing and/or higher sexual risk of female IDUs.

AIDS
The countries that have been most affected with AIDS among IDUs are mainly in the south-western part of the EU, notably Portugal, Spain, France and Italy(23). Incidence of AIDS varies greatly between countries, as does HIV, but the general trend is downward (Figure 26). This decline is probably the result of new treatments among IDUs that delay the onset of AIDS. Therefore, AIDS incidence is now considered as a less reliable indicator of HIV transmission than before about 1996. Spain, which had the highest yearly AIDS incidence among drug users, has recently been surpassed by Portugal, the only country not showing a decrease. This may indicate limited uptake of HIV treatment (as shown by a recent study) and/or increased HIV transmission during the 1990s. However, the increase in Portugal shows signs of levelling off during 2000.

Figure 26

Fig.26

NB

Cases reported by 31 December 2000, adjusted for reporting delays.
Sources

European Centre for the Epidemiological Monitoring of AIDS. See also statistical table.

Figure 16 OL AIDS cases diagnosed in 1999 in injecting drug users per million population

Figure 27

Fig.27
Sources

National focal points. For primary sources see complementary statistical table.

Hepatitis C
Prevalence of hepatitis C infection is higher and more similar across the EU than prevalence of HIV. Between 40 % and over 90 % of IDUs are infected with hepatitis C virus (HCV), even in countries with low rates of HIV infection such as Greece (see Figure 9, Chapter 1). Chronic HCV infection incurs substantial health problems, and in the long run (decades) may lead to serious health consequences, including severe liver damage and premature death. The proportion of chronic infections that lead to severe health problems is still very unclear, but there are recent indications that in IDUs it may be lower (perhaps 5 to 10 %) than previously thought (20 to 30 %) (3, 4). The extremely high levels of HCV infection among IDUs in Europe may, however, still lead to a large health burden due to liver disease among (ex-) IDUs over the coming decades.

Trends in hepatitis C infection, for the few countries which could provide these, show both important decreases and increases in Austria, Portugal and Greece depending on source (geographic location) and age group (Figure 27). These may reflect different populations of IDUs with a different epidemiology of infections. However, it is also possible that the trends reflect testing policies that relate to the recent introduction of HCV testing. For example, those with highest risk may participate first when a voluntary HCV test is offered such that prevalence in subsequent years appears to decline. Only following the trends over a longer period can confirm the apparent trends. This potential bias may be less important for HIV tests, which have been available for many years.

Hepatitis B
Prevalence of antibodies against hepatitis B virus (HBV) is also high, but seems less similar across the EU than prevalence of HCV. In the case of hepatitis B, the presence of antibodies indicates whether one has ever been infected, unlike for HCV and HIV, where a positive antibody test mostly indicates current infection. However, antibodies against HBV may also indicate vaccination. This means that vaccination practices, which may differ much between countries, need to be taken into account when interpreting HBV antibody prevalence. The proportion with no antibodies indicates IDUs who are still at risk of infection and should receive vaccination. Vaccination of IDUs is especially important as hepatitis B (also hepatitis A or D) infection can be very dangerous and even deadly if one is already infected with another hepatitis virus, such as HCV. In the EU, roughly between 20 and 60 % of IDUs have antibodies against hepatitis B. Self-reported data from studies in some countries suggests that only about 10 to 30 % of IDUs may have been fully vaccinated (5, 6, 7, 8). This suggests that a large potential health gain through vaccination exists.

Figure 17 OL Prevalence of antibodies against hepatitis B virus among injecting drug users in EU Member States, 1996-2000

Figure 28

Fig.28
Sources National focal points. For primary sources see complementary statistical table.

Easier to interpret than HBV antibodies is the prevalence of HBsAg (the serological marker that indicates that the hepatitis B virus is still present). This indicates current hepatitis B infection, which can be either recent or chronic infection. The level of HBsAg thus indicates the potential for severe long-term complications and for spread to others through injecting risk behaviour or sexual transmission. Prevalence of HBsAg is only available from a limited number of countries, but appears to differ much and is in some cases high (Figure 28). In northern Greece, IDUs in methadone programmes may have experienced an important outbreak of hepatitis B infection prior to 1998, as levels were extremely high in 1998 but strongly declined between 1998 and 1999. In Belgium, data from IDUs in treatment indicate a steady increase in current HBV infection (HBsAg) between 1997 and 1999. In Portugal, recent data indicate a decline in current HBV infection. In Norway, notification data indicate a strong increase in HBV (and HAV) infections among IDUs.

Other STDs, TB, endocarditis and Clostridium outbreak
Other infectious diseases that can be important among IDUs are TB, which is not transmitted by injecting drug use but is especially high among drug users in Spain and Portugal, due to its strong association with HIV infection and AIDS. Other sexually transmitted diseases (STDs), such as syphilis and gonorrhoea, can also be high among drug users, especially drug-using street prostitutes, if they have no access to low-threshold medical services. This may cause important transmission to non-drug users, while these STDs also form an important risk factor for HIV infection. Injecting drug users further often have high prevalence of other infections which can be life threatening, such as abcesses on injecting sites or endocarditis (infection of the heart valves), which can often easily be treated if services are available.

Between April and August 2000, a very large outbreak of Clostridium novyi infection occurred in Scotland, Ireland, England and Wales, resulting in 104 cases of severe illness and 43 deaths among young people. The outbreak was probably related to contaminated heroin in combination with specific modes of injection (intramuscular or subcutaneous rather than intravenous). It showed, in a dramatic way, how large the potential is for severe health problems among IDUs, which can be much larger and more life-threatening than health problems due to other and more prevalent patterns of drug use.

 

 

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