In Spain and throughout the world, the human immunodeficiency virus (HIV) and AIDS epidemic constitute a serious public health problem. The epidemic, now in its third decade, can be divided into three different stages. During the 1980s HIV spread rapidly. In Spain the main route of transmission was through intravenous drug use. Heterosexual mother-to-child transmission also occurred, whereas homosexual transmission between gay men was less notable. During this period mortality from AIDS became the leading cause of potential years of life lost. In the early 1990s prevention programs became more active, especially those aimed at the groups most vulnerable to HIV infection. Seroprevalence began to decline among intravenous drug users (IVDU), homosexual persons and female sex workers. Mid-way through the 1990s, with nearly 7000 cases of AIDS diagnosed and more than 5000 deaths annually, highly active antiretroviral treatment with protease inhibitors was introduced, and the incidence of AIDS and its mortality both decreased markedly.
Current estimates place the number of persons with HIV infection between 110 000 and 150 000, nearly one fourth of whom are unaware that they are infected. We can surmise that between 50% and 60% have contracted the disease through injection drug use, and 20% to 30% through risk behaviors for heterosexual transmission. Risk behaviors for homosexual transmission account for 15% to 25% of all current infections.
Current epidemiological data for HIV infection and AIDS1 indicate that the epidemic is waning, the number of new cases of HIV infection having decreased by almost 60% since the start of the 1990s. However, the rate of decrease in the incidence of new cases of AIDS diagnosed in Spain has leveled off.
Among IVDU, seroprevalence and the number of new HIV infections have decreased. In contrast, sexual transmission has become more frequent, especially among heterosexual persons and in women. (Seroprevalence among homosexual persons has decreased.) Sex partners of persons with HIV infection, especially partners of IVDU, have shown the most worrying trends. Among female sex workers seroprevalence remains below 2%.
Progression from HIV infection to AIDS is declining, but the interval between infection and diagnosis of HIV infection, when the virus can be transmitted to other persons and the carrier cannot benefit from antiretroviral treatment, needs to be drastically shortened. This would affect the incidence of AIDS and mortality from the epidemic. Efforts are also needed to improve the course of the epidemic in homosexual persons and partners of persons with HIV infection.
Further important challenges are to foment adherence to treatment, and to avoid the appearance of resistance to antiretroviral drugs and adverse events that make withdrawal of treatment necessary.
The 2001-2005 Multisectorial Plan for HIV infection and AIDS in Spain2 has set clear goals and defined specific indicators for prevention, which is envisioned as part of the wider system of health care in order to enhance coordination between prevention and care. The general population includes persons who are at low risk for HIV infection and who seek care frequently for other reasons unrelated with HIV, e.g., for primary care or gynecological consultations. Opportunities for new infections arise among persons in frequent or close contact with those who are HIV infected, persons who engage in risk behaviors, persons who are in habitual or occasional contact with centers that provide care for drug addicts, persons with sexually transmitted diseases, persons with sporadic sexual contacts, and female sex workers. The multisectorial plan therefore also foresees the use of preventive measures in centers for sexually transmitted diseases, and recommends sentinel surveillance for HIV infection to monitor the disease in selected populations that are targets for preventive interventions (IVDU, female sex workers, etc).
It is within this context that we should consider the study by the EPI-VIH Group, a research group with solid experience in HIV epidemiology.3 We should perhaps note that persons who use alternative centers that provide anonymous, voluntary HIV testing form a group whose risk profile differs from that of users ot other types of health care center.
The number of diagnoses of HIV infection decreased from 1058 in 1992-1993 to 304 in 2000-2001, and this trend was seen for all exposure categories except female sex workers. The decrease was greatest among IVDU. Similarly, the prevalence of HIV infection decreased from 14% to 2%, a trend seen for all types of transmission.
The decrease in IVDU may reflect a shift to other routes of administration and the results of risk-reduction programs offering needle exchange and methadone maintenance. These factors also contribute to the decrease in the number of new diagnoses of HIV infection.
Men who engage in homosexual or bisexual relations represent a much larger group of users at alternative centers than at other centers. The number of these users has remained more or less unchanged, and the prevalence of HIV infection in this group has decreased, particularly during the early years of the epidemic. The slowed rate of decrease in recent years, however, seems to indicate that some risk behaviors remain common in this group.
Among female sex workers the demand for counseling and HIV testing has increased, along with the prevalence
of HIV infection.
Although high-risk sexual practices are the most frequent reason for requesting HIV testing, the prevalence of HIV infection in this group of users has decreased, while the sex ratio in these users has approached one.
What measures should be considered for the future? For the present it appears that we are not diagnosing HIV infection in a timely manner: one third of the persons who develop AIDS did not know they were HIV infected.4 These are important deficiencies in the early diagnosis of HIV infection, and are particularly worrisome for individuals who do not clearly consider themselves as persons who engage in risk behaviors. Improvements in prevention and the effectiveness of antiretroviral treatment will depend on whether such deficiencies are corrected.
Sources of information also await consolidation and improvement. For example, greater coordination should be sought with epidemiological surveillance services that record new HIV infections (as in the regions of Asturias, Navarra, La Rioja and the Balearic Islands)5. These services make it possible to obtain information on the characteristics of persons with HIV infection in a timely manner. Such information is fundamental for planning preventive interventions and controlling HIV, and in responding to the health and social needs of persons who are currently infected. Progress is also needed in monitoring HIV infection in specific populations for which preventive activities are targeted (e.g., IVDU, homosexual persons, male and female sex workers).
Primary care services should play a larger role and be more closely involved in health promotion, especially in efforts aimed at patients who are not infected and have no known risk factors. A greater role for primary care in prevention is also desirable because the continuity and frequency of clinical contacts with large numbers of persons in the community offer a superb opportunity to disseminate information about prevention and to reinforce health-promoting behaviors.
Prevention is not an easy task, as there is no explicit demand for preventive interventions. For IVDU, such measures comprise strategies to reduce risk. To prevent mother-to-child-transmission, HIV testing for sexually active women is advisable. Occupational prevention requires efforts to reduce needlestick injuries. Once the general population becomes more knowledgeable about HIV infection, these practices will become long-term health- promoting habits.
To make further progress in our knowledge about and control of the HIV epidemic, we must make prevention our main goal, place prevention within the sphere of health care, and integrate preventive and health care measures more fully. Primary care should play a more active role in these efforts6.
Key Points
* Although the epidemic is remitting, HIV infection and AIDS still constitute a serious public health problem.
* A substantial number of persons who develop AIDS are unaware that they are HIV infected.
* Alternative centers fulfill the needs of specific groups within the general population.
* Primary care has a fundamental role to play in the early diagnosis of HIV infection.
