The changing face of the HIV epidemic in western Europe: what are the implications for public health policies?

Summary

In this review, we describe changes in dynamics of HIV transmission and shifts in affected populations in western Europe using HIV/AIDS surveillance data and published and unpublished reports. Despite substantial reductions in HIV-related morbidity and mortality since the introduction of highly active antiretroviral treatment, HIV continues to pose a major public health problem in western Europe. More than half a million people are living with an infection that remains incurable and requires costly lifelong treatment; many people remain unaware of their infection, and thousands of new infections continue to occur every year. Migrants from countries with a high prevalence of HIV/AIDS, notably sub-Saharan Africa, bear a disproportionate and increasing share of HIV throughout western Europe and, in most countries, account for the majority of heterosexually acquired HIV infections diagnosed in recent years. Prevention, treatment, and care must be adapted to reach migrant populations. Following a resurgence of risky sexual behaviour, HIV transmission may now be increasing among homosexual and bisexual men, and renewed safer sex campaigns are urgently needed.

Introduction

Over the past two decades, the HIV/AIDS epidemic has had profound and lasting effects on societies in western Europe, severely affecting some communities and resulting in major changes in sexual and drug-use behaviours. By the time the first AIDS cases were reported in the early 1980s,1, 2, 3, 4 HIV had already spread widely among homosexual and drug-user communities throughout western Europe. It has been estimated that HIV incidence peaked around 1983 among homosexual men and in 1987–88 among injecting drug users, with 120 000 homosexual and bisexual men infected by 1985, and 144 000 injecting drug users infected by 1989.⁵ Heterosexually acquired infections increased slowly during the late 1980s and early 1990s.

Extensive prevention programmes set up in the 1980s had a strong impact in altering behaviours that put people at risk for HIV infection, particularly among high-risk communities.6, 7, 8 Systematic screening of blood donations since 1985 virtually eliminated the risk of HIV transmission through blood transfusion.9, 10, 11, 12, 13, 14 In the 1990s, large-scale voluntary HIV testing of pregnant women followed by antiretroviral treatment of those found to be seropositive, and other interventions to reduce the risk of vertical transmission, were implemented.15, 16, 17, 18, 19 The rate of vertical transmission in Europe fell from 15·5% by 1994 to 2·6% after 1998.²⁰ Although the modality of pregnancy-related HIV testing can differ from country to country,15, 16, 17, 18, 19 the net result has been a substantial drop in the number of HIV-infected newborn babies and a continuing decline in the incidence of vertically acquired AIDS in infants younger than 1 year, from a peak of 127 cases in 1993 to 15 cases in 2002 (EuroHIV, unpublished data).

Highly active antiretroviral treatment, widely used in western Europe since 1996–97, has greatly reduced HIV-related morbidity and mortality,²¹ and resulted in substantial declines in AIDS incidence and deaths that cannot be fully explained by earlier decreases in HIV transmission.22, 23, 24, 25 Similar declines occurred in all countries except Portugal, a country with a much later epidemic primarily associated with drug use, but where a clear break in the epidemic curve suggests that the impact of treatment was also strong (figure 1).

At the start of the 21st century, HIV/AIDS nevertheless remains a communicable disease of major public health importance in western Europe. An estimated 520 000–610 000 people have an infection that remains incurable and needs extensive and costly treatment.26, 27, 28 The potential to infect others is lifelong, and the stigma of the infection is enduring. Moreover, large numbers of people remain unaware of their infection, and can therefore neither benefit from treatment nor take steps to reduce the risk of passing their infection to others.²⁹ An estimated 30000–40000 infections continue to occur every year.²⁶ We review the recent epidemiology of HIV in western Europe, highlighting changes in transmission dynamics and vulnerable populations, and discuss potential reasons for the emerging trends and their implications for prevention and control.