Surveillance of disease is a pillar of public health. It aims to monitor health-related problems and eventually to detect new ones; indirectly, it is also used to evaluate interventions. A quarter of century ago, the detection of unusual cases of non-Hodgkin lymphomas and Kaposi sarcoma among young people in the United States was made by the surveillance systems, leading to the diagnosis of what was later called AIDS.1
By the end of 2007, approximately 3 million people were living with HIV infection on the American continent. In their latest epidemiological update (2007), Joint United Nations Program on HIV/AIDS (UNAIDS) and World Health Organization estimated that in the Latin American and the Caribbean region (LAC), the proportion of infection by risk group was men who have sex with men (MSM), 26%; injection drug users (IDUs), 19%; clients of sex workers, 13%; female sex workers (FSWs), 4%; and other groups not well specified, 38%.2
Although in the Caribbean basin the ratio of women to men among people with HIV infection is close to 1, in most countries of the LAC, males are overrepresented among people living with HIV due to the predominance of MSM and high rates of males among IDUs. However, for large numbers of people (38%), the cause of infection is unknown. Most of the Latin American countries fall under the category of concentrated epidemic, where the size of population risk groups, the level of HIV prevalence, and its iteration with the general population are the main factors that determine the spread of HIV infection.
The decline of AIDS mortality and new AIDS cases were the first significant changes due to the introduction of multidrug antiretroviral treatment (ART) in 1996 in developed countries. Access to ART has increased in low-resource countries in the past few years. In Latin America and the Caribbean alone, almost 400,000 people were receiving ART in 2007, representing 64% coverage of the total ART need.3 As a comparison, the estimated coverage in the United States was around 56% in 2005.4 Nevertheless, this high coverage hides significant differences between countries and subregions.
As more funds are being invested in HIV, more data on interventions will be needed. Monitoring and evaluation of interventions and services will provide strategic information for national AIDS programs to improve response and promote accountability to governments, donors, and civil society. Moreover, international agencies such as World Health Organization, UNAIDS, Global Fund, and bilateral donors need to assess global and national progress toward the universal access target.
This special issue of Journal of Acquired Immune Deficiency Syndromes dedicated to Latin America and the Caribbean focuses on strategic information issues, including surveillance of the epidemic and monitoring of sexual behaviors, and underlines progress and weaknesses in the production, analysis, and use of information for improving response. The issue presents updates on key epidemiological data in the region, including behavioral surveillance in the general population and in vulnerable groups, including migrants; it analyzes the impact of preventive interventions in different contexts, including sex work, and of national responses.
Hall et al present the epidemiological situation in the United States and Canada where the first AIDS cases were detected in 1981. HIV/AIDS continue to be a public health problem in the United States even after more than 25 years of epidemic, and perhaps is time not to talk about epidemic but rather an endemic state. Rates of HIV transmission remain a challenge in both countries as overall diagnosis rates have not decreased in recent years. HIV continues to affect minority groups disproportionally, with more than 72% of reported AIDS cases in the United States being African Americans or Hispanics. The new HIV estimates published recently reveal that about 56,000 people were newly infected in 2007,5 whereas in Canada, incidence seems to be stable. Aboriginal people in Canada are also disproportionably affected. HIV diagnoses continue to increase among MSM in both countries. Despite the improved services, a large proportion of people were diagnosed late in the disease process.
Migration, both legal and illegal, from the LAC countries to the United States has a long history. Migration to the United States was the driving factor of the early Mexican HIV epidemic, and it may continue to be so in the future. Magis-Rodriguez et al present the results of a study conducted on the United States/Mexican border comparing demographic and behavior variables between Mexicans with a history of migration to the United States in the past 12 months and nonmigrant Mexicans from the same community. Overall, migrant workers, both men and women, reported more HIV risk behaviors, including more sexual partners and drug use, than nonmigrants in the past year. Because HIV respects neither borders nor walls, international collaboration is needed to tackle the HIV epidemic between transiting countries.
As in many other regions, Latin America is a mosaic of people and cultures. Honduras is one of the countries highly affected by HIV infection. Paz-Bailey et al conducted a preliminary study to measure the rates of HIV and sexually transmitted diseases. Using a modified snowball sampling technique, they conducted a survey among Garifunas in Honduras. Garifunas are a minority population in the Caribbean coast of Central American countries, descendents of former slaves who escaped from the Caribbean colonies. Their language and culture are very different from the rest of the population in Honduras. Results showed that among Garifunas in Honduras, there is a high prevalence of HIV and herpes simplex virus-2 when compared with the rest of the country. Although some risk factors for HIV infection, such as the prevalence of chlamydia and gonorrhea, and a lack of basic knowledge about HIV transmission are high, preventive behaviors like consistent condom use are low. This confirms the vulnerability of this population. Prevention programs should be adapted by taking into account such differences.
Sexual behavior continues to be the main determinant of the risk of HIV infection. Therefore, monitoring trends on sexual behaviors among the most at-risk populations and the general population is relevant for monitoring programs' outcomes. Bozon et al analyzed data from standard demographic population surveys in 8 countries in Latin America, focusing on trends in the timing of early sexual and reproductive events, sexual activity during adulthood, and measurement of homosexual/bisexual behaviors. They find evidence of early male initiation of sex compared with women of the same age inducing a long premarital period for males, which favors experiences with sex workers. But variations in the sexual behavior patterns within the region are important, very far from the image of cultural homogeneity associated to Latin America.
Clients of sex workers are one of the bridge populations for HIV infection in the general population in many Latin American and Caribbean countries. It has also been demonstrated that this group can claim most new HIV infections in some countries in Asia. Two articles present the results of interventions that target sex workers.
Sabidó et al described the outcomes of an integrated prevention and treatment approach implemented in 3 sexually transmitted infection (STI) clinics for FSWs in Guatemala where more than 1000 women were enrolled. From an analysis of HIV and STI prevalence trends, it seems that STIs were declining when HIV incidence was increasing. The study confirms that the interaction and relation between HIV and STI incidence remain unclear.
The second FSW article is presented by Strathdee et al. The authors reviewed the efficacy of an intervention, based on the social cognitive theory, to increase condom use among FSWs in Tijuana and Ciudad Juarez, situated on the Mexico-United States border. The study concludes that increases in self-efficacy significantly predicted increased condom use among FSWs. However, when dealing with FSWs who are also IDUs, evidence of effectiveness is limited. Selected and targeted interventions are needed for this group.
The largest proportion of HIV infection in the LAC region is represented by the men who have sex with men. Sanchez et al. presented and confirmed evidence on the important risk factor of ulcerative sexually transmitted infection for acquiring HIV infection through an analysis of a observational cohort of men who have sex with men recruited in Lima. The high prevalence of those STI and high incidence of HIV infection among whom has sex with men in Lima is a call for improving effective interventions to prevent new HIV infections.
Two articles looked at the national response to the HIV epidemic from different angles. Caceres et al review the basic epidemiological information about HIV and the response in Peru, and they analyze the changes produced by the HIV/AIDS epidemic in the society as a whole, particularly in terms of social movements and their dynamic relationship with the state. The authors conclude with concrete proposals on action that may fill the gaps on national response and strengthen the results of interventions.
Monitoring trends in the epidemic is the core objective of HIV surveillance. Interpreting these trends, whether in terms of natural progression of the epidemic or of result of interventions, is a challenge for public health analysis. Halperin et al, using multiple sources of information, review the dynamics of HIV infection in Dominican Republic. They aim to assess whether the changes are natural or induced by the national response to HIV epidemic. The national level of HIV prevalence has clearly declined from the peak in the late 1990s, probably due to interventions. However, HIV prevalence remains relatively high in MSM, with no evidence of significant decrease in this population. The authors conclude that in Dominican Republic, the epidemic has stabilized in recent years after declining in early 2000. They fear that because of the risk of complacency and relaxation of preventive behaviors related to the increasing number of people accessing to care and treatment, the incidence rate will rise.
One of the first preventive measures implemented in many countries was screening blood donations for HIV infection as blood-borne transmission is the most efficient route for acquiring HIV infection. Blood banks are one of the core services in the third level of health services. Alonso et al reviewed the policies established in the region for blood donations. The analysis of criteria used in the region for deferral of potential blood donors shows inconsistencies that may affect the necessary safe blood supply. Health personnel have assumptions and misconceptions that may exclude suitable donors. The authors proposed that blood donor deferral criteria should be revised according to relevant epidemiological evidence and social legitimacy.
During the past few years, most Latin American countries have had access to Global Fund resources and have been working closely with international agencies and donors. Surprisingly enough, only a few of them have a consolidated HIV/STI surveillance system that could provide more reliable estimates of HIV prevalence or new infections and describe their distribution and trends. For instance, in Central America, apart from sporadic studies, most of the regional indicators come from the multicenter study performed by the Programa para fortalecer la respuesta en Centro America al VIH (PASCA) project (a USAID-funded prevention project for Central America and local collaborators between 2001 and 2002). Efforts to increase data availability are under way, but many countries are still far behind.
In a recent publication, the Global HIV Prevention Group6 emphasized the need to strengthen HIV surveillance and other related HIV strategic information systems to better understand their own epidemic and its sources of HIV infection to close the gap in the national response. Countries should be supported to better collect, compile, analyze, and, last but not the least, appropriately use data for improving programs. “Knowing your epidemic” and the impact of the national response is one of the core strategies for implementing appropriate national strategic plans. The articles published in this issue give evidence of progress toward better measuring the epidemic, monitoring the response, and evaluating interventions, but a lot need to be done in the area of strategic information to enhance appropriate interventions.