The emerging genetic diversity of HIV. The importance of global surveillance for diagnostics, research, and prevention.

The discovery of highly divergent strains of human immunodeficiency virus (HIV) not reliably detected by a number of commonly used diagnostic tests has underscored the need for effective surveillance to track HIV variants and to direct research and prevention activities. Pathogens such as HIV that mutate extensively present significant challenges to effective monitoring of pathogens and to disease control. To date, relatively few systematic large-scale attempts have been made to characterize and sequence HIV isolates. For most of the world, including the United States, information on the distribution of HIV strains among different population groups is limited. We describe herein the implications resulting from the rapid evolution of HIV and the need for systematic surveillance integrated with laboratory science and applied research. General surveillance guidelines are provided to assist in identifying population groups for screening, in applying descriptive epidemiology and systematic sampling, and in developing and evaluating efficient laboratory testing algorithms. Timely reporting and dissemination of data is also an important element of surveillance efforts. Ultimately, the success of global surveillance network depends on collaboration and on coordination of clinical, laboratory, and epidemiologic efforts.

Community planning: a national strategy to improve HIV prevention programs.

Beginning in fiscal year (FY) 1994, the Centers for Disease Control and Prevention (CDC), in collaboration with health departments and other human immunodeficiency virus (HIV) prevention partners, set in motion a significant innovation in HIV prevention programs: HIV Prevention Community Planning. This process, implemented by all 65 health departments receiving HIV prevention funds from CDC, requires that the identification and prioritization of HIV prevention needs to be a shared responsibility between the health departments administering the funds and representatives of the affected communities for whom the services are intended. Guidance for this planning process strongly embraces the notion that high priority HIV prevention strategies and interventions must have a sound basis in behavioral and social science and that program planning must begin with an accurate assessment of the epidemiology of the current and projected future HIV epidemic. Rather than mandate a single standardized process for all of the 65 jurisdictions, CDC guidance provides flexibility for each jurisdiction to configure a planning process responsive to its own unique circumstances. However, all planning activities must be guided by 13 essential principles. This article will describe the principles and logistics of HIV Prevention Community Planning, identify the potential program benefits of this new undertaking, and describe implementation challenges.

An overview of the effectiveness and efficiency of HIV prevention programs.

Because of the enormity of the HIV-AIDS epidemic and the urgency for preventing transmission, HIV prevention programs are a high priority for careful and timely evaluations. Information on program effectiveness and efficiency is needed for decision-making about future HIV prevention priorities. General characteristics of successful HIV prevention programs, programs empirically evaluated and found to change (or not change) high-risk behaviors or in need of further empirical study, and economic evaluations of certain programs are described and summarized with attention limited to programs that have a behavioral basis. HIV prevention programs have an impact on averting or reducing risk behaviors, particularly when they are delivered with sufficient resources, intensity, and cultural competency and are based on a firm foundation of behavioral and social science theory and past research. Economic evaluations have found that some of these behaviorally based programs yield net economic benefits to society, and others are likely cost-effective (even if not cost-saving) relative to other health programs. Still, specific improvements should be made in certain HIV prevention programs.

Excess deaths in Africa from HIV: confirmed and quantified.

PIP: While most reasonable observers acknowledge that HIV causes AIDS and death in Africa, others have argued that HIV is responsible for neither death nor AIDS on the continent. Recent findings from a two-year prospective cohort study by Mulder and colleagues, however, should put to rest claims by these latter skeptics. Mulder's epidemiological study was conducted in rural Uganda to quantify excess mortality associated with HIV infection. It was found that young adults testing positive for antibody to HIV were sixty times as likely to die during the subsequent two-year observation period as were otherwise similar persons who tested negative. Mortality was well in excess of background rates in all age groups, but was highest in men and women aged 25-34 years who were most commonly infected with HIV. These findings should dispel any notion other than the reality that HIV infection is clearly an important cause of premature mortality throughout the world. One may realize the association between HIV infection and death even without believing that HIV causes AIDS.^ieng

Preventive services guidelines for primary care clinicians caring for adults and adolescents infected with the human immunodeficiency virus.

Primary care clinicians caring for persons infected with the human immunodeficiency virus greatly contribute to public health efforts to combat the human immunodeficiency virus/acquired immunodeficiency disease epidemic in the United States. Primary care clinicians can assess the prevention needs of persons infected with the human immunodeficiency virus and ensure that needed prevention services are received.

Commentary: condoms and HIV/STD prevention--clarifying the message.

In the United States and throughout the world, the majority of human immunodeficiency virus (HIV) infections are sexually transmitted. an estimated 12 million other sexually transmitted diseases occur annually in the United States. Avoiding sexual intercourse altogether or restricting sex to partners known to be uninfected will prevent infection; this needs to be promoted as the most effective strategy. Studies show that correct and consistent use of latex condoms is highly effective in preventing sexually transmitted HIV infection and other sexually transmitted diseases. The effectiveness of condoms depends on individual behavior leading to correct and consistent use. Further studies are needed to maximize the use and effectiveness of condoms for those who choose to be sexually active as well as to develop and evaluate other methods, particularly those more under the control of women. In the interim, our prevention message should be clear: When used correctly and consistently, condoms are highly effective; when used otherwise, they are not.

Perspectives on HIV/AIDS epidemiology and prevention from the Eighth International Conference on AIDS.

The Eighth International AIDS Symposium in Amsterdam, the Netherlands, provided updated scientific and programmatic information on the human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) to thousands of interested participants. As in the other scientific areas, the amount of information presented in epidemiology and prevention was overwhelming; however, the scientific progress described was steady but incremental. This commentary summarizes progress made in three selected areas that were highlighted during the meeting's scientific session and a fourth that received widespread media attention: (1) the epidemiology of HIV/AIDS in heterosexual women; (2) tuberculosis as an increasing opportunistic pathogen in HIV-infected persons; (3) prevention research, practice, and policy; and (4) preliminary reports of severe immunodeficiency in persons without evident HIV infection. In order to stem HIV transmission worldwide, a safe and effective vaccine is urgently needed. Currently, in the absence of such a vaccine, it is crucial for all of the world's communities to apply the best science-based prevention methods available.

Risk of hepatitis B and human immunodeficiency virus transmission to a patient from an infected surgeon due to percutaneous injury during an invasive procedure: estimates based on a model.

The objective was to estimate the probability of sporadic hepatitis B virus (HBV) and human immunodeficiency virus (HIV) transmission to a patient from an infected surgeon due to percutaneous injury during an invasive procedure. Risk was estimated based on a model involving three probabilities: A, the probability that the surgeon will sustain a percutaneous injury during an invasive procedure; B, the probability that the sharp object causing the injury and now contaminated with the surgeon's blood will contact the patient's wound; and C, the probability that infection would be transmitted to the patient after such an exposure. The probability of transmission during one procedure is p = A x B x C. The probability of transmission to at least one patient during N procedures is 1-(1-p)N. Values for A, B, and C were estimated from prospective studies. The estimated probability of transmission from an infected surgeon to a patient during a single procedure is 0.00024-0.0024% for HIV and 0.024-0.24% for HBV if the surgeon is positive for hepatitis B e antigen (HBeAg). The estimated probability of transmission to at least one patient during 3,500 procedures (estimated to be performed during an HIV-infected surgeon's remaining working life) is 0.81-8.1% for HIV; 57-100% for HBV if the surgeon is an HBeAg carrier. These estimates represent population averages and may not necessarily apply to a particular procedure performed by a particular surgeon, for which the risk may be considerably lower or higher than the estimated average. This risk assessment, which is based on limited data and does not take clusters of transmission into account, predicts that the risk of sporadic HBV transmission from infected surgeons to patients due to percutaneous injury during an invasive procedure is small and that the risk of HIV transmission is less than that for HBV. More data are needed to understand both sporadic and epidemic transmission in order to further reduce patient risk.

Simian immunodeficiency virus needlestick accident in a laboratory worker.

The macaque monkey infected with simian immunodeficiency virus (SIV) is an animal model of the acquired immunodeficiency syndrome. We investigated a laboratory worker who was exposed by needlestick accident to blood from an SIV-infected macaque. Seroreactivity to SIV developed within 3 months of exposure, with antibody titres peaking from the third to the fifth month and declining thereafter. Polymerase chain reaction for SIV sequences and cultures of peripheral-blood mononuclear cells failed to show infection. Inoculation of an SIV-negative monkey with blood from the worker did not cause infection. Animal-care and laboratory workers should adhere strictly to recommended procedures to avoid accidental exposures when working with SIV-infected animals or specimens.

AIDS in bisexual men in the United States: epidemiology and transmission to women.

BACKGROUND: Homosexual and bisexual men with acquired immunodeficiency syndrome (AIDS) differ, and bisexual men play an important role in the sexual transmission of human immunodeficiency virus (HIV) to women. METHODS: To describe AIDS in these groups, we examined AIDS cases reported nationally through June 1990. RESULTS: Among 65 389 men who reported having had sex with men since 1977, 26% were bisexual. More Black (41%) and Hispanic men (31%) than White men (21%) reported bisexual behavior. Bisexual men were twice as likely to report intravenous drug use (20%) as were homosexual men (9%), regardless of race or ethnicity. Among 3555 women with heterosexually acquired AIDS, 11% reported sexual contact with a bisexual man and no other risk factor, although in some states approximately half reported such contact. In 1989, the AIDS rate due to sex with a bisexual man was three and five times higher among Hispanic and Black women, respectively, than among White women. CONCLUSIONS: Differences between bisexual and homosexual men with AIDS and the relative importance of AIDS in women due to sexual contact with bisexual men should be considered in the development of HIV prevention programs.

Communicating surveillance, epidemiologic, and laboratory information on HIV infection and AIDS.

As the epidemic of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) has evolved over the past 10 years, the Centers for Disease Control (CDC) has been at the forefront of the scientific efforts that have characterized HIV-AIDS research. Because of CDC's central role in these efforts, the medical and public health communities have come to depend on the agency for prompt reporting of new developments related to the epidemiology of HIV infection and AIDS and for advice on risk management, prevention, and control. CDC disseminates this information through epidemiologic updates and prevention guidelines published in the periodical, Morbidity and Mortality Weekly Report, through articles in scientific journals and summary tabulations of AIDS case data and HIV seroprevalence data, and through interviews and presentations at scientific meetings. These formal information dissemination activities are supplemented with training and support efforts directed at health care providers, health department and laboratory personnel, educators, and centralized HIV-AIDS information resources. As questions are answered, controversies resolved, and new research applications explored, CDC will continue to provide the medical and public health communities with the most recent epidemiologic information and recommendations developed to help direct efforts in HIV prevention and risk reduction.

Prevalence of the human immunodeficiency virus among university students.

BACKGROUND AND METHODS: To estimate the magnitude of the human immunodeficiency virus (HIV) epidemic among university students, we conducted a blinded HIV-seroprevalence survey at 19 universities throughout the United States. HIV-antibody testing was performed on blood collected for routine medical purposes at the student health centers of the participating institutions. At each campus, from 250 to 1000 blood specimens were collected consecutively and tested for HIV antibodies by enzyme-linked immunosorbent assay and Western blot analysis. Nonidentifying demographic data were linked with the test results. RESULTS: Of 16,863 specimens in the sample, 30 (0.2 percent) were positive for antibodies to HIV. Positive specimens were found at 9 of the 19 schools. All were from students over 18 years old; 19 (63 percent) were from students over 24. All but 2 of the 30 infected students were men. The seroprevalence rate for men was 0.5 percent (95 percent confidence interval, 0.3 to 0.7), and for women it was 0.02 percent (95 percent confidence interval, 0.002 to 0.066). Seroprevalence increased with age--from 0.08 percent (95 percent confidence interval, 0.04 to 0.15) for students 18 to 24 years old to 1.0 percent (95 percent confidence interval, 0.2 to 2.9) for those 40 or older. CONCLUSIONS: HIV infection is present on U.S. university campuses, although the rate appears to be far lower than that of populations known to be at high risk. The potential clearly exists, however, for the further spread of HIV infection in this population, and preventive measures are needed.