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Objective: To estimate the number of persons infected with the human immunodeficiency virus (HIV) living in the United States and the change in HIV infection prevalence since 1984., Design: We estimated HIV prevalence from 3 data sources. We estimated past HIV infection rates from a statistical procedure based on national acquired immunodeficiency syndrome (AIDS) case surveillance data and estimates of the time from HIV infection to AIDS diagnosis. We also analyzed HIV prevalence data from 2 national surveys, a survey of childbearing woman and a household survey of current health status. We used other data sources to adjust these survey estimates to include groups not covered in the surveys., Results: Approximately 0.3% of US residents (650,000-900,000 persons) were infected with HIV in 1992. Approximately 0.6% of men (including adolescent boys > or = 13 years of age) were infected, including approximately 2% of non-Hispanic black men and 1% of Hispanic men. Approximately 0.1% of women (including adolescent girls > or = 13 years of age) were infected, including approximately 0.6% of non-Hispanic black women. Approximately half of all infected persons were men who had sex with men, and one fourth were injecting drug users. The prevalence of HIV infection increased from 1984 to 1992, with a greater relative increase among women than men., Conclusions: The 3 different data sources and methods are consistent in estimating that 650,000 to 900,000 persons were infected with HIV in the United States in 1992. Among adolescents and adults of both sexes, the proportion infected was substantially higher among non-Hispanic blacks and Hispanics than among non-Hispanic whites. HIV-related illness will be a major clinical and public health problem in the United States for years to come.

National unlinked sentinel surveillance data were used to describe trends in prevalent human immunodeficiency virus infection among injection drug users entering drug treatment programs in the United States from 1988 through 1993. During this 6-year period, unlinked testing was performed on 70,882 specimens from injection drug users at 60 sentinel sites. The annual change in seroprevalence was estimated for each site by odds ratios obtained from logistic regression models fit within site-specific age and race/ethnicity subgroups. Overall trends for age and race/ethnicity subgroups across sites were described by summary odds ratios calculated using the inverse variance method. A decrease was observed among younger (age less than 30 years) whites both in areas with high (10% or higher) and low (less than 10%) prevalence, although this decrease was significant only in high-prevalence areas (odds ratio = 0.90, 95% confidence interval 0.81-0.99). Seroprevalence also decreased among older whites in high-prevalence areas, although this decrease was not significant (odds ratio = 0.95, 95% confidence interval 0.89-1.00). Seroprevalence remained stable among all other age and race/ethnicity subgroups. Stable seroprevalence among the dynamic population of injection drug users entering treatment suggests continued transmission among these individuals in both high- and low-prevalence areas of the United States.

Trends in seroprevalence of the human immunodeficiency virus (HIV) were examined among patients attending sentinel clinics for sexually transmitted diseases (STDs) throughout the United States. Cross-sectional, unlinked (blinded) surveys of HIV seroprevalence were conducted annually within clinics in 40 metropolitan areas. From 1988 to 1992, 552,665 specimens were tested in 80 STD clinics. The overall HIV seroprevalence was 33% (range among metropolitan areas: 5-52%) among gay and bisexual men, 3% (range: 0.3-11%) among heterosexual men, 2% (range: 0.1-11%) among women, and 10% (range: 0.5-45%) among heterosexual injecting drug users (IDUs). Controlling for clinic, age, and race/ethnicity, HIV seroprevalence decreased among all gay and bisexual men, but especially among white gay and bisexual men from 32% in 1989 to 22% in 1992. Among heterosexual men and women, HIV seroprevalence decreased among whites and, to a lesser degree, Hispanics, but remained essentially stable among African-Americans over time. Among heterosexual IDUs, seroprevalence was also unchanged. These results reflect changes in the HIV epidemic, which is becoming increasingly characterized by infected heterosexuals and IDUs, especially within minority populations.

To evaluate human immunodeficiency virus type 1 (HIV-1) infection among patients of primary care physicians, we performed anonymous, unlinked HIV-1 antibody testing on leftover blood specimens submitted to 10 large commercial clinical laboratories for complete blood cell count or hematocrit determination, the most commonly ordered diagnostic tests. From January through August 1990, 55,613 specimens submitted by general internists, pediatricians, and family practitioners were sampled; 1,104 (2.0%) had HIV-1 antibody. Seroprevalence among the laboratories varied 50-fold, from 0.3 to 12.4%. The HIV-1 prevalence at each laboratory was not always consistent with the AIDS incidence in the area served by the laboratory. Overall the seroprevalence was almost eight times higher in men (3.9%) than in women (0.5%). Specimens from seropositive persons, especially from men, were unevenly distributed among the physician practices; only three practices submitted approximately 50% of all specimens from seropositive men. These data indicate that a few physicians treat the majority of HIV-1-infected primary care patients. The HIV-1 prevalence among specimens at a clinical laboratory is thus determined by whether few physicians submit specimens to that laboratory. These results could be of use, for instance, in analyzing proposals to mandate physician reporting of HIV-1 infection. The high HIV-1 prevalence among laboratory specimens underscores the potential for exposure to HIV-1-infected blood by clinical laboratory personnel and emphasizes the need for universal precautions for all blood specimens.

The Centers for Disease Control and Prevention has developed guidelines for determining HIV seroprevalence among patients seeking medical care at acute-care hospitals. The guidelines enable hospital staff members to perform a simple, rapid, and inexpensive survey to determine seroprevalence among the patient population, protecting the anonymity of those who are tested. The guidelines are based on national experience with large-scale anonymous, unlinked HIV serosurveys. The data from a rapid assessment survey are particularly useful for evaluating the need to provide routine, voluntary HIV counseling and testing and treatment for HIV infection. Beyond that, such data can be used in targeting education efforts, in reinforcing the use of appropriate universal precautions, in resource allocation, and in determining the need for further studies of HIV infection among the population in the hospital catchment area.

Objective: To describe trends in the prevalence of human immunodeficiency virus (HIV) among socially and educationally disadvantaged US youth., Design: Analysis of demographic and geographic trends of HIV infection among Job Corps students from January 1988 through December 1992., Setting: The Job Corps is a national training program for disadvantaged and out-of-school youth. POPULATION SCREENED: Youths aged 16 to 21 years who entered the Job Corps residential training centers during the survey period., Main Outcome Measure: Trends in prevalence of HIV infection among Job Corps students stratified by sex, age, race, and region of the country., Results: Of the 269,956 Job Corps students screened, 812 (0.3%) tested positive for the antibody to HIV type 1. Seroprevalence of HIV for young men decreased from 3.6 per 1000 in 1988 to 2.2 per 1000 in 1992 (chi 2 test for trend, P < .001). Seroprevalence for young women increased from 2.1 per 1000 in 1988 to 4.2 per 1000 in 1990 (P = .001), with seroprevalence remaining stable from 1990 through 1992. The decreasing trends in HIV prevalence among men and increasing trends among women were primarily due to changes in seroprevalence in African-American students., Conclusions: The overall prevalence of HIV infection of three per 1000 is high, given the youth of Job Corps students. The significant rise in HIV rates among female Job Corps students provides evidence of the increasing risk of infection for socioeconomically disadvantaged young women. Reasons for the declining trend in HIV prevalence among male Job Corps students are not clear. Efforts to prevent the spread of HIV infection among adolescents must focus on the group that is hardest to reach--out-of-school and impoverished youth.

To determine human immunodeficiency virus (HIV) seroprevalence among hospital patients in three rural community-based hospitals in southern Georgia, we anonymously tested patients 15 to 54 years old for antibodies to HIV-1 from residual blood specimens collected for routine diagnostic purposes. Data collected included age, sex, race, hospital service, presenting condition, physician's knowledge of HIV infection status, and discharge diagnosis. Of 1319 patients tested, seven (0.5%, 95% confidence interval = 0.2% to 1.1%) had antibodies to HIV-1. Of those seven, five had HIV infection unsuspected by their physicians, and four had an infectious disease. HIV seroprevalence was 0.5% for both men and women, 1.0% for blacks, and 0.3% for whites. HIV-positive patients were found on all hospital services. These results suggest that in rural southern Georgia hospitals, HIV should be routinely considered in the differential diagnosis of conditions that may be related to HIV. In addition, these data demonstrate a need for medical services or referral networks for HIV-related illnesses and a need for continuing HIV counseling and testing offered by local health departments in rural southern Georgia.

Between May 1988 and September 1989, 829 human immunodeficiency virus type 1 (HIV-1)-seropositive donors were identified from 3,919,000 units of blood donated at 20 United States (US) blood centers. Of the 829,512 (62%) were interviewed to assess behavioral characteristics of the largest subgroup, men reporting sex with men, use of the confidential unit exclusion (CUE) and reasons for donation among all donors. Among 216 men reporting sex with men, 97 percent had male and 72 percent had female sexual contact since 1978. The majority identified themselves as bisexual (29%) or heterosexual (26%). Although 61 percent of 512 donors were aware of their risk behavior at donation, including 57 percent of those infected through heterosexual transmission, only 5 percent used the CUE. Reasons for donation included failure to read carefully (46%) or comprehend (15%) the deferral materials, pressure to donate (27%), a desire to be tested for HIV-1 (15%), and a reliance on screening to identify infected blood (10%). Reasons given for a perception of being at low risk included no recent risk behaviors, infrequent risk behaviors, or modification of risk behaviors. To reach high-risk donors, centers should assess whether referral materials provide necessary medical information and are clearly written for persons with diverse cultural and language backgrounds. Staff should be encouraged to avoid the use of culturally stigmatized terms and behaviors that may be perceived as high pressure.

Background and Methods: To evaluate the epidemiology of infection with human immunodeficiency virus type 1 (HIV-1) in selected urban communities in the United States, we instituted active surveillance at sentinel hospitals by anonymous testing of samples of blood specimens for HIV-1 antibody. To reflect better the rates of HIV-1 seroprevalence in the communities served by the sentinel hospitals, we excluded specimens from all patients with diagnoses that are often associated with HIV infection., Results: From January 1988 to June 1989, 89,547 specimens were tested at 26 hospitals in 21 cities. The overall rate of HIV-1 seroprevalence was 1.3 percent, but it ranged from 0.1 to 7.8 percent according to hospital (median, 0.7 percent). The age distribution of persons seropositive for HIV-1 was similar across hospitals and closely paralleled that of persons with the acquired immunodeficiency syndrome (AIDS). In areas of low seroprevalence, HIV-1 infections were highly concentrated among men. However, the male-to-female ratio (median, 7.0) decreased steadily with an increasing overall rate of seroprevalence (P less than 0.001); at the five hospitals with the highest rates of seroprevalence, the median male-to-female ratio was only 2.9. The median black-to-white ratio of HIV-1 seroprevalence was 1.8, but at hospitals with low rates of seroprevalence the rates in blacks and whites were nearly equal. At two hospitals in the communities with the highest prevalence of AIDS, 1.1 to 3.8 percent of adolescents 15 to 19 years old and 18 to 22 percent of all men 25 to 44 years old were seropositive for HIV-1., Conclusions: In these sentinel, urban populations there is tremendous variation in the rate of HIV-1 infection (over 70-fold). The very high seroprevalence at some sentinel hospitals indicates the need for routine screening for HIV-1 infection among some groups of patients, regardless of clinical presentation.

Primary care outpatients provide a good sentinel population for monitoring levels and trends of HIV infection in the United States. Because a broad cross section of the population seeks primary medical care, excess blood from specimens routinely collected for other purposes is available for anonymous, unlinked HIV testing, and all age groups and both sexes can be sampled. The CDC family of surveys includes two surveys of primary care outpatients: (a) a survey of 100,000 blood specimens per year submitted by more than 6,000 primary care physicians to a national diagnostic laboratory for complete blood count or hematocrit and (b) a survey of approximately 10,000 blood specimens per year from a network of 242 primary care physicians. Each survey has different advantages: the laboratory-based survey has a large sample from a large population base, and the physician network survey has a well-defined patient population in which each patient's clinical condition can be determined. In the primary care physician network, a concurrent study of clinical patterns of disease in patients with recognized HIV infection provides additional information on the clinical syndromes associated with HIV infection and estimates of the occurrence of unrecognized HIV infection.

Sharing of equipment used to inject illicit drugs intravenously is a risk factor for human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS). Systematic surveillance of HIV infection among intravenous drug users (IVDUs) in the United States is essential to monitor the HIV epidemic and to target and evaluate prevention programs for IVDUs and their partners. The most accessible segment of the largely covert population of IVDUs are those in drug treatment programs. In collaboration with State and local health departments and drug abuse treatment agencies, the Centers for Disease Control is conducting blinded (serologic test results not linked to identifiable persons) and nonblinded (in which clients voluntarily agree to participate) surveys of IVDUs entering drug treatment in 39 U.S. metropolitan areas. The same protocol is used in all participating drug treatment centers. Blinded surveys will be carried out annually to determine HIV seroprevalence rates in eligible IVDUs entering drug treatment and to monitor trends over time. Each year, nonblinded surveys of IVDUs entering drug treatment will assess self-reported drug use and sexual behaviors to help design educational interventions and to detect changes in behavior over time. This sentinel surveillance system, using a standardized methodology, will provide the best national and regional data available on the seroprevalence of HIV among IVDUs and the relationships of drug use, sexual behaviors, and HIV serologic status of IVDUs.

During 1987-89, the Centers for Disease Control (CDC), in collaboration with State and local health departments, other Federal agencies, blood collection agencies, and medical research institutions, implemented a national sentinel surveillance system for human immunodeficiency virus (HIV) infection. This ongoing surveillance system, known as the CDC family of HIV seroprevalence surveys, uses standardized survey and HIV serologic testing procedures in a group of sentinel populations from geographically diverse metropolitan areas, States, and Territories of the United States. As of September 1989, sentinel surveillance for HIV infection was being conducted in 41 States, Puerto Rico, and 39 metropolitan areas, including the District of Columbia. Information from this system complements AIDS surveillance data to assist health officials to direct resources and develop strategies for HIV prevention and health-care programs.

Blood donors make up the largest group in the United States that is tested for human immunodeficiency virus, type 1 (HIV) antibody. The blood donor population is ideal for detecting and quantifying uncommon or unrecognized modes of HIV transmission in the general population because persons at known risk for HIV infection are excluded from donating blood. The national HIV surveillance program consists of a centralized computer database of information on all donations at selected American Red Cross blood centers, which together account for about a quarter of the blood supply, and all donations at 20 regional blood centers where seropositive blood donors are interviewed to evaluate their risk factors for HIV infection and to determine their epidemiologic characteristics and motives for donation. Trends in HIV prevalence and incidence within specific demographic subgroups are determined for first-time and repeat donors. Combining the trends with HIV-risk profile data from seropositive donors provides a rate for HIV seropositive donors with no identified risk. Epidemiologic and behavioral data from seropositive donors will help in the development and evaluation of future donor deferral strategies.