HIV Surveillance --- United States, 1981--2008

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Within 1 year of the initial report in 1981 of a deadly new disease that occurred predominantly in previously healthy persons and was manifested by Pneumocystis carinii pneumonia and Kaposi's sarcoma, the disease had a name: acquired immune deficiency syndrome (AIDS). Within 2 years, the causative agent had been identified: human immunodeficiency virus (HIV). On the 30th anniversary of the epidemic, to characterize trends in HIV infection and AIDS in the United States during 1981--2008, CDC analyzed data from the National HIV Surveillance System. This report summarizes the results of that analysis, which indicated that, in the first 14 years, sharp increases were reported in the number of new AIDS diagnoses and deaths among persons aged ≥13 years, reaching highs of 75,457 in 1992 and 50,628 in 1995, respectively. With introduction of highly active antiretroviral therapy, AIDS diagnoses and deaths declined substantially from 1995 to 1998 and remained stable from 1999 to 2008 at an average of 38,279 AIDS diagnoses and 17,489 deaths per year, respectively. Despite the decline in AIDS cases and deaths, at the end of 2008 an estimated 1,178,350 persons were living with HIV, including 236,400 (20.1%) whose infection was undiagnosed. These findings underscore the importance of the National HIV/AIDS Strategy focus on reducing HIV risk behaviors, increasing opportunities for routine testing, and enhancing use of care (1).

HIV infection is notifiable in all 50 states and the District of Columbia (DC); AIDS is now notifiable as stage 3 HIV infection. For this report, AIDS data reported to CDC by the end of June 2010 from 50 states and DC were analyzed to determine the annual number of AIDS diagnoses, deaths among persons with AIDS, and persons living with AIDS from 1981 through 2008. Surveillance data were adjusted for reporting delays and missing risk-factor information, but not for incomplete reporting (2). Additionally, by using 1) HIV and AIDS data for persons aged ≥13 years at diagnosis from 40 states that have had confidential name-based HIV infection reporting since at least January 2006 and 2) AIDS data from 11 areas, CDC estimated the annual number of persons living with HIV infection using extended back-calculation (3). The estimated number of undiagnosed HIV infections was calculated by subtracting the number of diagnosed infections from the estimated overall HIV prevalence. HIV prevalence rates per 100,000 population were calculated for 2008 based on postcensal estimates from the U.S. Census Bureau.

From 1981 to 1992, the estimated annual number of persons aged ≥13 years with newly diagnosed AIDS grew rapidly, from 318 to 75,457. From 1981 to 1995, the estimated annual number of deaths among persons with AIDS increased from 451 to 50,628 (Figure). These increases were followed by declines of 45% in AIDS diagnoses, from 1993 (75,263) to 1998 (41,462) and 63% in deaths, from 1995 (50,628) to 1998 (18,851). The declines began to level off in 1999, and AIDS diagnoses and deaths remained fairly stable at an average of 38,279 AIDS diagnoses and 17,489 deaths per year during 1999--2008. As a result, the estimated number of persons aged ≥13 years living with AIDS more than doubled from 1996 (219,318) to 2008 (479,161) (Figure).

At the end of 2008, an estimated 1,178,350 persons aged ≥13 years were living with HIV infection, including 236,400 (20.1%) whose infections had not been diagnosed (Table). Most (75.0%) persons living with HIV were male, and 65.7% of the males were men who have sex with men (MSM). HIV prevalence rates among blacks or African Americans (1,819.0 per 100,000 population) and Hispanics or Latinos (592.9) were approximately eight times and two and a half times the rate among whites (238.4) (Table). Greater percentages of those living with HIV infection had undiagnosed HIV among persons aged 13--24 years (58.9%) and 25--34 years (31.5%) than among those aged 34--44 years (18.0%), 45--54 years (13.8%), 55--64 years (11.9%), and ≥65 years (10.7%). Greater percentages of undiagnosed HIV also were observed among males with high-risk heterosexual contact (25.0%) and MSM (22.1%) than among those in other transmission categories. Greater percentages of undiagnosed HIV also were observed among Asians or Pacific Islanders (26.0%), and American Indians or Alaska Natives (25.0%), than among blacks or African Americans (21.4%), whites (18.5%), and Hispanic or Latinos (18.9%) (Table).

Reported by

Lucia Torian, PhD, New York City Dept of Health and Mental Hygiene. Mi Chen, MS, Philip Rhodes, PhD, H. Irene Hall, PhD, Div of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, CDC. Corresponding contributor: Mi Chen, CDC, [email protected], 404-639-8336.

Editorial Note

Three decades after the first cases were reported in the United States, HIV infection is no longer inevitably fatal. Highly active antiretroviral therapy suppresses viral replication for decades, allowing patients to enjoy longer and healthier lives and making them less infectious to others (4). A recent study of 3,400 heterosexual couples in Africa found that use of antiretroviral therapy reduced HIV transmission risk by 92% (4). HIV-related mortality, perinatal transmission, and the number of new HIV diagnoses among injection drug users have plummeted (2). Nucleic acid testing now can detect HIV as early as 9 days after infection, enhancing the safety of the blood and organ supply and providing opportunities for early detection and disease intervention, including partner notification (5). Preexposure prophylaxis and topical microbicides are promising biomedical interventions (6). The scientific progress in immunology, virology, pharmacology, and clinical management that led to these successes occurred at a faster pace than was imaginable in 1981, when the first cases of AIDS were identified.

HIV prevention efforts averted an estimated 350,000 HIV infections during 1991--2006 and saved $125 billion in medical care costs (7). However, despite these efforts and widespread knowledge of how to prevent HIV, CDC estimates that 50,000 persons are infected each year in the United States. More than half of the newly infected are MSM, and nearly half are black or African American (3). In addition, the findings in this report indicate that, of the estimated 1,178,350 living with HIV infection in the United States, 20.1% had undiagnosed HIV infections.

Surveillance data show that the proportion of HIV diagnoses occurring in MSM continues to grow. HIV incidence among MSM has increased steadily since the early 1990s (3). In 2009, MSM accounted for 57% of all persons and 75% of men with a diagnosis of HIV infection in the 40 states with longstanding, confidential, name-based HIV infection reporting (2). Syphilis and gonorrhea are endemic among MSM; outbreaks or hyperendemic sexually transmitted infections have been reported from many communities where HIV infection also is prevalent, further increasing the risk for acquiring and transmitting HIV (8).

Late diagnosis of HIV infection is common. Among persons with newly diagnosed HIV in 2008, 33% developed AIDS within 1 year of initial HIV diagnosis (2). These persons likely were infected an average of 10 years before diagnosis. During this period, they missed opportunities to obtain medical care and to prevent unwitting transmission of HIV to others. Persons with a late diagnosis of HIV infection also are at greater risk for short-term mortality than those who receive an HIV diagnosis earlier in the course of infection. Initiation of care soon after diagnosis is recommended, yet a meta-analysis of 28 studies from multiple U.S. regions found that 28% of persons did not enter care within 4 months of HIV diagnosis (9). In addition, an estimated 41% of HIV-infected persons did not average at least two care visits in a year (9), as recommended by the U.S. Department of Health and Human Services (10).

The findings in this report are subject to at least three limitations. First, reported HIV data used in the extended back-calculation method represent only a portion of persons in the United States who received a diagnosis of HIV infection; some areas with high incidence, including Maryland and DC, did not contribute HIV data. Availability of HIV data from these areas will increase accuracy of future prevalence estimates. Second, not all persons with HIV have received a diagnosis of HIV infection, and so, have not been reported to the public health surveillance system; data must be estimated for persons with undiagnosed HIV. Finally, the data have been adjusted statistically to account for delays in reporting new cases and deaths and for missing risk factor information, which might result in less stable results (2).

The National HIV/AIDS Strategy (1) has three primary goals: 1) reduce HIV incidence, 2) increase access to care and improve health outcomes for persons living with HIV, and 3) reduce HIV-related health disparities. The strategy refocuses efforts toward intensified HIV prevention in communities where HIV infection is most prevalent, using a combination of effective strategies that seek to optimize entry into and retention in care and maintenance of viral suppression. CDC, in partnership with state and local health departments, will use surveillance data to evaluate the measurable outcomes of this strategy, including new diagnoses, early detection, entry into care, retention in care, and viral suppression, as well as progression to AIDS and death.

References

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10. Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents. Washington, DC: US Department of Health and Human Services; 2011. Available at http://www.aidsinfo.nih.gov/contentfiles/adultandadolescentgl.pdf. Accessed May 26, 2011.