Book contents
- Frontmatter
- Contents
- Introduction
- Participants
- Non-Participant Contributors
- Part 1 Transmissible diseases with long development times and vaccination strategies
- Part 2 Dynamics of immunity (development of disease within individuals)
- Part 3 Population heterogeneity (mixing)
- Part 4 Consequences of treatment interventions
- Part 5 Prediction
- AIDS: modelling and predicting
- Staged Markov models based on CD4+ T-lymphocytes for the natural history of HIV infection
- Invited Discussion
- Short term projections by dynamic modelling in large populations: a case study in France and The Netherlands
- Bayesian prediction of AIDS cases and CD200 cases in Scotland
- Some scenario analyses for the HIV epidemic in Italy
- Relating a transmission model of AIDS spread to data: some international comparisons
- Estimation of the rate of HIV diagnosis in HIV-infected individuals
- Effects of AIDS public education on HIV infections among gay men
- Changes in sexual behaviour and HIV control
- The time to AIDS in a cohort of homosexual men
The time to AIDS in a cohort of homosexual men
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- Introduction
- Participants
- Non-Participant Contributors
- Part 1 Transmissible diseases with long development times and vaccination strategies
- Part 2 Dynamics of immunity (development of disease within individuals)
- Part 3 Population heterogeneity (mixing)
- Part 4 Consequences of treatment interventions
- Part 5 Prediction
- AIDS: modelling and predicting
- Staged Markov models based on CD4+ T-lymphocytes for the natural history of HIV infection
- Invited Discussion
- Short term projections by dynamic modelling in large populations: a case study in France and The Netherlands
- Bayesian prediction of AIDS cases and CD200 cases in Scotland
- Some scenario analyses for the HIV epidemic in Italy
- Relating a transmission model of AIDS spread to data: some international comparisons
- Estimation of the rate of HIV diagnosis in HIV-infected individuals
- Effects of AIDS public education on HIV infections among gay men
- Changes in sexual behaviour and HIV control
- The time to AIDS in a cohort of homosexual men
Summary
The incubation period of AIDS is a key characteristic in understanding the HIV and AIDS epidemic, both clinically and epidemiologically. The incubation period distribution (IPD) provides information about the probability of progression to AIDS as it changes with time since infection with HIV. The IPD also provides the link between the HIV infection rate and the occurrence of AIDS cases over time, and is an essential feature in back calculation procedures (Brookmeyer and Gail 1988). Knowledge of the IPD creates the opportunity to make more reliable projections (Hendriks et al. 1992), which are necessary for health-care planning.
Cohort study data relating to development of AIDS are inevitably incomplete in dates of seroconversion (infection) or development of AIDS, or both. This incompleteness has inspired a variety of approaches. We used a multiple imputation procedure, with four related models, each covering different assumptions, to investigate the sensitivity of the estimated IPD regarding the imputation method. The imputation procedure was used to provide the unobserved interval between seroconversion and enrolment for those individuals who were already HIV infected at enrolment. We can exclude observations relating to individuals who received antiviral and or prophylactic treatment designed to delay the onset of AIDS. The results obtained from data such as these will be valuable in future to aid the understanding of the effects of new therapies on the evolution of the AIDS epidemic.
The IPD was estimated using data available at February 1990 from all homosexual and bisexual men with HIV seropositive blood samples (n = 348; aged 25–45 years), who were part of a larger cohort study in Amsterdam.
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- Information
- Models for Infectious Human DiseasesTheir Structure and Relation to Data, pp. 485 - 487Publisher: Cambridge University PressPrint publication year: 1996