Current Trends Update: Acquired Immunodeficiency Syndrome -- United States

Between June 1, 1981, and January 13, 1986, physicians and health departments in the United States notified CDC of 16,458 patients (16,227 adults and 231 children) meeting the acquired immunodeficiency syndrome (AIDS) case definition for national reporting (1-3). Of these, 8,361 (51% of the adults and 59% of the children) are reported to have died, including 71% of patients diagnosed before July 1984. The number of cases reported each 6-month period continues to increase (Figure 1), although not exponentially, as evidenced by the lengthening case-doubling times (Table 1). Cases have been reported from all 50 states, the District of Columbia, and three U.S. territories.

Adult patients. Among adult AIDS patients, 60% were white; 25%, black; and 14%, Hispanic. Ninety percent were 20-49 years old, and 93% were men. Although the race, age, and sex distribution of adult AIDS patients has remained relatively constant over time, significant changes have occurred in the distribution of specific diseases reported. Pneumocystis carinii pneumonia (PCP) continues to be the most common opportunistic infection reported among AIDS patients, accounting for 43% of reported opportunistic diseases; incidence of PCP continues to increase relative to other reported opportunistic diseases among AIDS patients (p 0.0001). PCP accounted for 35% of the diagnosed AIDS-associated diseases before January 1984 and 47% of those diagnosed from January 1985 to December 1985. The increase in PCP was associated with a decrease in Kaposi's sarcoma (KS), the second most common AIDS-associated opportunistic disease. Before December 1984, KS accounted for 21% of reported diagnoses; between January 1985 and December 1985, KS accounted for 13% of reported diagnoses. Among all AIDS patients, 63% have been diagnosed with PCP; 24%, with KS; 14%, with candida esophagitis; 7%, with cytomegalovirus (CMV) infections; 7%, with cryptococcosis; 4%, with chronic herpes simplex; 4%, with cryptosporidiosis; 3%, with toxoplasmosis; and 3%, with other opportunistic diseases only. These values tend to underestimate the number of diseases diagnosed in a given patient, because health-care providers frequently do not provide follow-up information on diseases that occur after the case has initially been reported.

A total of 15,243 (94%) AIDS patients can be placed in groups* that suggest a possible means of disease acquisition: men with homosexual or bisexual orientation who have histories of using intravenous (IV) drugs (8% of cases); homosexual or bisexual men who are not known IV drug users (65%); heterosexual IV drug users (17%); persons with hemophilia (1%); heterosexual sex partners of persons with AIDS or at risk for AIDS (1%); and recipients of transfused blood or blood components (2%). The remaining 984 (6%) have not been classified by recognized risk factors for AIDS.

AIDS patients reported as not belonging to recognized risk groups are investigated by local health officials to determine if possible risk factors exist. Since 1981, 1,206 AIDS patients reported to CDC were initially identified on the original case report form as not belonging to a risk group. Of these individuals, 398 were from countries where heterosexual transmission may account for many AIDS cases. Of the remaining 808, information was incomplete on 178 patients due to: death (116), refusal to be interviewed (24), or loss to follow-up (38). Two hundred ninety-seven cases are still under investigation. Interviews or other follow-up information were available on the remaining 333 patients. Based on this information, risk factors were ultimately identified in 197 (59%) individuals; 25 (8%) were found not to meet the criteria of the surveillance definition for AIDS and no risk was identified on 111 (33%) AIDS patients. In interviews of the 111 patients for whom no risk was identified, 39 (35%) gave histories of gonorrhea and/or syphilis, indicating that these AIDS patients were at risk for other sexually transmitted infections. Of 57 men interviewed, 15 (26%) gave histories of sexual contact with a female prostitute.

Reported cases have increased in all patient groups (Table 2). The relative proportion of AIDS cases among most risk groups has remained stable (Table 3). The proportion of AIDS cases associated with blood transfusions has increased from 1% to 2% (p = 0.015). Due to the long period between infection with human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) and development of AIDS, the impact of serologic screening of blood donations and deferral of those at increased risk cannot be expected to be reflected yet in national AIDS reporting. In the groups not classified by recognized risk factors, the proportion of AIDS patients born outside the United States has declined from 4% to 2% (p 0.0001).

Pediatric patients. Among 231 AIDS patients under 13 years old, 19% were white; 60%, black; and 20%, Hispanic. Fifty-five percent were male. Fifty-eight percent were diagnosed with PCP; 19%, with disseminated CMV; 15%, with candida esophagitis; 6%, with cryptosporidiosis; 4%, with KS; and 22%, with other opportunistic diseases only. One hundred seventy-four (75%) pediatric patients came from families in which one or both parents had AIDS or were at increased risk for developing AIDS; 33 (14%) had received transfusions of blood or blood components before onset of illness, and 11 (5%) had hemophilia. Risk-factor information on the parents of the 13 (6%) remaining cases is incomplete. Although 57% of pediatric patients have been reported within the last year, 72% were actually diagnosed before 1985. Pediatric patients have been reported from 23 states, Washington, D.C., and Puerto Rico; cases reported per state ranged from one to 91 (median three). Seventy-five percent of the cases have been reported from New York, Florida, New Jersey, and California. Reported by State and Territorial Epidemiologists; AIDS Program, Center for Infectious Diseases, CDC.

Editorial Note

Editorial Note: The incidence of AIDS continues to increase. In 1982, 747 cases were reported; in 1983, 2,124 were reported (a 184% increase); in 1984, 4,569 were reported (a 115% increase); and in 1985, 8,406 were reported (an 84% increase). From analyses of past trends, further increases are expected for 1986; however, the percentage increase in 1986 is likely to be smaller than that noted in 1985.

The number of AIDS cases that have not been classified into previously identified risk groups is not increasing proportionately faster than the number of cases in identified risk groups. Past experience would suggest that many cases currently under investigation will be reclassified.

Currently reported AIDS cases have resulted from HTLV-III/LAV exposure up to 7 years before diagnosis (4); the possibility of longer incubation periods cannot be excluded. Since HTLV-III/LAV infection persists in an individual, persons previously infected continue to remain at risk for developing AIDS. Due to the long period between infection and development of AIDS, transfusion-associated cases are expected to continue (4). However, voluntary donor deferral by those at increased risk for AIDS and serologic testing of donated blood and plasma for HTLV-III/LAV antibody--implemented in March 1983 and spring 1985, respectively--have greatly reduced the potential for HTLV-III/LAV transmission through transfusion (4-6).

The increase in previously diagnosed pediatric AIDS cases reported within the past year reflects improved reporting as well as inclusion in the case definition of histologically confirmed diagnoses of chronic lymphoid interstitial pneumonitis in children under 13 years of age (3). Since most pediatric AIDS cases result from perinatal transmission of HTLV-III/LAV, the race/ethnicity and geographic distribution of pediatric AIDS patients is similar to that of reported AIDS cases among adult females.

Planned prospective studies of incidence and prevalence of HTLV-III/LAV infection should determine whether current reports of patients meeting the AIDS case definition for national reporting accurately reflect the distribution of infected persons. Persons meeting the AIDS case definition are only a small percentage of all persons infected with HTLV-III/LAV (7). CDC uses the existing case definition for surveillance purposes, because other manifestations of HTLV-III/LAV infection are less specific and less likely to be consistently reported nationally.

References

1. CDC. Update: acquired immunodeficiency syndrome (AIDS)--United States. MMWR 1984;32:688-91.

2. Selik RM, Haverkos HW, Curran JW. Acquired immune deficiency syndrome (AIDS) trends in the United States, 1978-1982. Am J Med 1984;76:493-500.

3. CDC. Revision of the case definition of acquired immunodeficiency syndrome for national reporting--United States. MMWR 1985;34:373-5.

4. Peterman TA, Jaffe HW, Feorino PM, et al. Transfusion-associated acquired immunodeficiency syndrome in the United States. JAMA 1985;254:2913-7. 5 CDC. Prevention of acquired immune deficiency syndrome (AIDS):

report of inter-agency recommendations. MMWR 1983;32:101-4. 6. CDC. Update: Public Health Service workshop on human

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