in the estimates of HIV incidence and prevalence (Centers for Disease Control, 1990):

  1. Estimates of new HIV infections for very recent periods are less likely to be accurate than estimates for the more distant past.

  2. It is likely that the incubation distribution I(d) has changed over time as new therapies have been introduced for people who are HIV positive but are asymptomatic. In addition, changes over time in the stage of infection at which infected people are diagnosed would include changes in I(d). Furthermore, there is uncertainty about whether the I(d) distributions obtained from cohort studies of homosexual men or hemophiliacs accurately reflect the I(d) distribution for all infected people.

  3. The time series of CDC counts of AIDS cases is not the time series of new AIDS cases, for two reasons. First, the case definition of AIDS has been expanded twice (in 1985 and 1987); consequently, the growth in AIDS cases is exaggerated. Second, there are delays from the time of diagnosis to the time a case is reported to the CDC. These delays would result in counts of diagnosed cases that are increasingly less complete as one moves from the past to the present. Some cases are never reported; these can be regarded as cases with infinite delays in reporting. The CDC estimates that its surveillance system identifies 70-90 percent of HIV-infection-related deaths and that it therefore provides a minimum estimate of HIV-infection-related mortality (Centers for Disease Control, 1991). Consequently, CDC counts must first be corrected for the changes in the case definition and for reporting delays before they can be used. Reporting delays may have changed over time, imparting further uncertainty into the corrected series, At (Harris, 1990).

REFERENCES

Arras, J.D. (1988) The fragile web of responsibility: AIDS and the duty to treat. Hastings Center Report 8(Suppl.):10-20.


Brandt, A.M. (1988) AIDS and metaphor: toward the social meaning of epidemic disease. Social Research 55:413-432.

Brookmeyer, R. (1991) Reconstruction and future trends of the AIDS epidemic in the United States. Science 253:37-42.


Campbell, A.M. (1931) The Black Death and Men of Learning. New York: Columbia University Press.

Centers for Disease Control (CDC) (1990) HIV prevalence and AIDS case projections for the United States: report based on a workshop. Morbidity and Mortality Weekly Report 39:(RR-16):1-31.

Centers for Disease Control (CDC) (1991) Mortality attributable to HIV infection/AIDS—United States, 1981-1990. Morbidity and Mortality Weekly Report 40:41-46.

Centers for Disease Control (CDC) (1992) HIV/AIDS Surveillance Report . Atlanta, Ga.: Centers for Disease Control.



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