Modelling HIV/AIDS epidemics in sub-Saharan Africa using seroprevalence data from antenatal clinics.
OBJECTIVE
To improve the methodological basis for modelling the HIV/AIDS epidemics in adults in sub-Saharan Africa, with examples from Botswana, Central African Republic, Ethiopia, and Zimbabwe. Understanding the magnitude and trajectory of the HIV/AIDS epidemic is essential for planning and evaluating control strategies.


METHODS
Previous mathematical models were developed to estimate epidemic trends based on sentinel surveillance data from pregnant women. In this project, we have extended these models in order to take full advantage of the available data. We developed a maximum likelihood approach for the estimation of model parameters and used numerical simulation methods to compute uncertainty intervals around the estimates.


RESULTS
In the four countries analysed, there were an estimated half a million new adult HIV infections in 1999 (range: 260 to 960 thousand), 4.7 million prevalent infections (range: 3.0 to 6.6 million), and 370 thousand adult deaths from AIDS (range: 266 to 492 thousand).


CONCLUSIONS
While this project addresses some of the limitations of previous modelling efforts, an important research agenda remains, including the need to clarify the relationship between sentinel data from pregnant women and the epidemiology of HIV and AIDS in the general population.
Salomon
J A
JA
Global Programme on Evidence for Health Policy, World Health Organization, 1211 Geneva 27, Switzerland. salomonj@who.int
Murray
C J
CJ
D000328:Adult; D017954:Africa South of the Sahara / Q000453:epidemiology; D000554:Ambulatory Care Facilities; D003625:Data Collection; D004196:Disease Outbreaks; D005260:Female; D015658:HIV Infections / Q000453:epidemiology*; D015528:HIV Seroprevalence / Q000639:trends*; D006801:Humans; D016013:Likelihood Functions; D015233:Models, Statistical; D011159:Population Surveillance; D011247:Pregnancy; D011295:Prenatal Care