Short-term prediction of HIV infection and AIDS: a critique of the Working Group's Report to the Department of Health.
The Report of the Working Group on the Short-Term Prediction of AIDS/HIV (the Cox Report) is reviewed mainly to assess its calculations of the numbers of people in England and Wales who are infected with the human immunodeficiency virus (HIV). Two main methods are used in the report to estimate this total--the direct method and the back projection method. The direct method estimates the number of people infected with HIV by attempting to specify the numbers of people in various at-risk groups, and the percentage infected in those groups. Of particular significance are the estimates given for male homosexuals. The Cox Report suggests that between 4.0% and 4.7% of the male population aged between 16 and 59 are homosexual, and that between 1.9% and 4.5% of these are HIV antibody-positive. The basis on which these estimates are made is not substantiated by the Report, and it is quite possible that the upper limit given for HIV prevalence in male homosexuals represents an understatement of the actual number by a factor of 2.5 or more. The back projection method estimates HIV prevalence from the numbers of cases of the acquired immunodeficiency syndrome (AIDS) and the incubation function, the relationship between HIV infection and the probabilities of AIDS in each of the years following infection. Using this method the Cox Report fails to produce results that are in accordance with our knowledge of how the epidemic developed during the 1980s. As a consequence of this the various calculations of numbers of HIV antibody-positives to 1987 given in the Cox Report are all almost certainly underestimates.(ABSTRACT TRUNCATED AT 250 WORDS)
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D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology*; D004739:England / Q000453:epidemiology; D015658:HIV Infections / Q000453:epidemiology*; D006716:Homosexuality / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D015995:Prevalence; D014852:Wales / Q000453:epidemiology