ORIGINALES

Coment. It is necessary to know who gets HIV infected

Comentario. La necesidad de saber quién se infecta

Santiago Pérez Hoyos

Escuela Valenciana de Estudios en Salud (EVES).

Twenty-five years ago, in the summer of 1981, the first reports of cases of pneumocystis pneumonia and Kaposi's sarcoma amongst men who had had sexual relations with other men in California and New York were published. This marked the beginning of what would later be defined as the AIDS epidemic. From that moment on, our country has shown constant interest in discovering as much as possible about the characteristics and evolution of AIDS cases and developing the most appropriate strategies for combating this problem. As Castilla et al¹ observed in their article published in Gaceta Sanitaria; the largest group of AIDS cases registered in Spain corresponded to the injection drug user (IDU) transmission category. But following the appearance, towards the end of 1996, of High Activity Anti-Retroviral Therapy (HAART), epidemiological interest changed radically. AIDS, and above all mortality associated with it, has ceased to be the main source of concern because the number of casualties ceased to be the main worry, as the number of cases declined drastically, while the HIV infection became a chronic problem.

However, this change in the way in which the problem manifested itself has not necessarily implied a reduction in the number of new cases of infection. At the recent XVI International AIDS Conference which was held in Toronto², it was explained that, in the whole world, there are now a total of 36 million people living with HIV and that the rate of infection is currently running at about 4.1 million people per year. This highly significant number of new cases is now closely related to an epidemic of injection drug use in the countries of Eastern Europe and South-East Asia, which are reproducing patterns of epidemic the HIV experienced in Spain towards the end of the 1980s. These new cases are also associated with increases in heterosexual HIV transmission observed in southern Africa and India, and with an increase in homosexual transmission of the disease detected in Europe and the USA.

This change in the epidemiological pattern of the HIV epidemic in our context, with the fall in the number of AIDS cases due to antiretroviral treatments, the introduction of policies aimed at reducing harm to IDUs, and changes in the ways in which drugs are taken, should not distract us from the need to update the epidemiological data that we have on HIV. Yet our main source of information on this subject, the registry of AIDS cases, has now become totally inadequate. As Castilla et al¹ explain, both the availability of registry recording new cases of HIV infection and the records available for the Autonomous Communities analysed in their study, provide a picture of the current situation and the current evolution of the epidemic. But judicial rulings against a ministerial order to create an Information System on New Cases of HIV Infection (SINIVIH)³ have lamentably meant that it has been impossible to extend this work to the national level. Thus we must content ourselves with only a partial vision of the recent evolution of HIV in Spain that may not necessarily faithfully reflect what has really occurred.

The paper by Castilla et al¹ shows the clear downward trend in the number of new cases of HIV infection, above all amongst IDUs. Yet this type of approach does not necessarily reflect the reality of the epidemic, because a simple reduction in the number of IDUS, this is, in the number of people at risk, would suggest a fall in the rate of incidence for the whole population even though the incidence of HIV might remain constant. However, other investigators⁴ do seem to corroborate this fall in the incidence of HIV, although perhaps not on such a high level as suggested by Castilla et al. On the other hand, such an important fall in this group caused an increase in the relative percentile weight of heterosexual transmission, despite the fact that there was also an evident decrease in the number of cases. The data presented do not reflect the surge in the incidence of homosexual infection observed in the cohort of the Centros de Información y Prevención (Information and Prevention Centres) of the Comunidad Valenciana and in other European cohorts.

All of this highlights the importance of avoiding complacency and of not lowering our guard when combating HIV infection in the countries of Western Europe. In these countries, as in Spain, despite the levelling off or fall in the number of new cases of HIV infection, it is important to stress that these often show quite worrying characteristics. The great weight of sexual transmission and its specific incidence amongst disfavoured collectives, such as immigrants from both sub-Saharan Africa and Latin America, means that it is necessary to adapt preventive measures specifically tailored to meet their needs. On the other hand, the high percentage of cases of late diagnoses indicates the need to continue emphasising and encouraging early diagnosis of the infection and the fact that HIV is a problem that affects everyone and not just marginal collectives.

Bibliografía

1. Castilla J, Lorenzo JM, Izquierdo A, Lezaun ME, López I, Moreno-Iribas C, et al. Characteristics and trends of newly diagnosed HIV-infections (2000-2004). Gac Sanit. 2006;20:442-8.

2. Reports and summaries from reporters. AIDS 2006 - XVI International AIDS Conference [Updated on 8 Sept 2006]. Available from: http://www.aids2006.org

3. Noguer I, Tello O, Pollan M, López-Abente G, Hernández Pezzi G. Condiciones precarias para el control de la epidemia del VIH. Gac Sanit. 2005;19:351-3.

4. Hurtado I, Alastrue I, Ferreros I, Del Amo J, Santos C, Tasa T, et al. Trends in HIV testing, serial HIV prevalence and HIV incidence among persons attending a Center for AIDS Prevention from 1988 to 2003; increases in HIV incidence in men who have sex with men in recent years? Sex Transm Infect. 2006 Jun 6; [Epub ahead of print].