HIV and AIDS | Hepatitis B and C
HIV has shown strong epidemic spread among IDUs in the new EU Member States of the Baltic region, following massive epidemics in eastern Europe (EuroHIV, 2004) (see box ‘HIV and AIDS in eastern Europe’). Rates of newly diagnosed cases peaked in Estonia and Latvia in 2001, and in Lithuania in 2002, but more recently rates have fallen dramatically. This pattern is typical of HIV epidemics among IDUs. It arises because the core group of IDUs at highest risk all become infected in a short period of time, following which incidence falls because of a lack of susceptible IDUs and then stabilises at a level that depends on the rate of recruitment of new IDUs at high risk. However, an additional effect of behaviour change cannot be excluded and, if true, this could in part be the result of specific interventions (see ‘Prevention of drug-related infectious diseases’).
In the EU-15 countries, rates of newly diagnosed HIV cases have remained low in recent years, with the exception of Portugal. However, comparisons at the EU level are incomplete as HIV case reporting data remain unavailable (Spain and Italy) or are only starting to become available (France) for some of the countries most affected by AIDS. Portugal showed a very high rate of 88 per million in 2003, but also a large decrease since 2000 (when the rate was 245 per million). This decrease has to be interpreted with caution as European data reporting was only implemented in Portugal in 2000.
Seroprevalence data from IDUs (per cent infected in samples of IDUs) are an important complement to HIV case reporting data. Repeated seroprevalence studies and routine monitoring of data from diagnostic tests can validate trends in case reporting and can also provide more detailed information on specific regions and settings. However, the prevalence data are from a variety of sources that, in some cases, may be difficult to compare, and they should therefore be interpreted with caution.
The recent increases recorded in the HIV case reporting are mostly confirmed by the available seroprevalence data; for example, in Latvia, prevalence in national treatment samples of tested IDUs rose from 1.5 % (5/336) in 1997 to 14 % (302/2 203) in 2001 and then fell to 7 % (65/987) in 2003. In Austria, where HIV case reporting data for IDUs are not available, HIV prevalence among national samples of (direct) drug-related deaths suggests some increase, to 7 % (11/163) in 2003 from 1 % (1/117) in 1998, but numbers are small and the trend is not statistically significant.
In 2002 and 2003, HIV prevalence among IDUs, mostly those in drug treatment, showed wide variation within and between countries, ranging from 0 % in Bulgaria, Hungary, Slovenia and Slovakia to a maximum of 37.5 % (54/144) in one city in Italy (2003, Bolzano – users in treatment and prisons) (120). The highest prevalence rates in national samples (over 10 % in 2002–03) were found in Italy, Latvia and Portugal (121); in Spain, data for 2001 suggest a very high prevalence, but more recent data are lacking (122).The highest prevalence rates in regional and local samples (over 20 % in 2002–2003) were reported from Spain, Italy, Latvia and Poland (123), although recent data have not been provided from some countries and areas with high prevalence in previous years. In Latvia and Poland, local studies suggest recent transmission of HIV, based on the very high prevalence among young IDUs (124). In the case of the Polish study, this recent transmission is confirmed by a prevalence of 23 % among a sample of 127new injectors (125).
Time trends in prevalence also differ between countries. Although there have been recent outbreaks in the Baltic region, HIV seroprevalence data from samples of IDUs suggest a decrease since the mid-1990s in some of the most affected countries (Spain, France and Italy), followed by a stabilisation in recent years (126). However, if seroprevalence is high and stable, transmission is likely to continue. Data for new IDUs strongly suggest ongoing, and even increased, transmission in Spain between 1999 and 2000. In some other countries (France 2001–03, Portugal 1999–2000) local and regional data on new and young IDUs suggested some (increased) transmission, but sample sizes are too small for the trends to be statistically significant (127). On the other hand, it should be noted that in several countries HIV prevalence among IDUs remained very low during 2002–03. HIV prevalence was less than 1 % in the Czech Republic, Greece (national data), Hungary, Slovenia, Slovakia, Finland, Romania (data for only 2001), Bulgaria and Norway (data for Oslo). In some of these countries (e.g. Hungary), both HIV prevalence and hepatitis C virus (HCV) prevalence are among the lowest in the EU, suggesting low levels of injecting risk (see section ‘Hepatitis B and C’ below).
HBM – homosexual and bisexual men
IDU – injecting drug users
HC – heterosexual contact
Transmission group not reported
Data shown for the three main transmission groups and for cases with no transmission group reported.
Countries not included are France, the Netherlands (data not available for the whole period) and Cyprus (no data available).
Source: EuroHIV; data reported by 31 December 2003.
In Latvia, the incidence of AIDS related to IDU increased from 0 cases in 1997 to an estimated 19 cases per million population in both 2002 and 2003 (128). However, the EU country with the highest incidence remains Portugal, with 33 cases per million, although this figure has been decreasing since 1999. AIDS incidence due to IDU in the EU peaked in the early 1990s and declined thereafter. The most affected country used to be Spain, where incidence peaked at 124 cases per million in 1994, but by 2003 this figure had declined to an estimated 16 per million.
The decline in AIDS incidence in the late 1990s is the result of the introduction in 1996 of highly active antiretroviral therapy (HAART), which prevents the development of AIDS in people infected with HIV (see box on HAART). In the case of IDUs, HIV prevention measures may also have played an important role and, in some countries, a decrease in the number of injectors may have been a factor (see ‘Drug injecting’).
Annual incidence data show that, until 2002, the greatest number of new cases of AIDS in the EU could be attributed to intravenous drug use; subsequently, this mode of transmission was overtaken by heterosexual sex, reflecting changes in the epidemiology of HIV in the preceding years (Figure 15). It should be noted, however, that infection patterns can differ greatly between individual countries (129).
(121) The data for Portugal and Italy are not limited to IDUs and may thus underestimate prevalence among IDUs.
(124) IDUs aged under 25: 33 % infected among 55 young IDUs in Poland and 20 % among 107 young IDUs in Latvia.