Understanding the relative effects of HIV-1 epidemics on men and women is an important pre-requisite for interpreting surveillance data collected at antenatal clinics and for understanding the demographic impact of such epidemics.
On the basis of gender differentials in HIV-1 seroprevalence apparent in data collected in community surveys, it has been suggested that epidemics may typically have a disproportionate effect on women in sub-Saharan African countries. However, recent national estimates of adult mortality indicate that, in general, AIDS is having a greater impact on men. In this paper, we consider whether these two apparently contradictory findings can be reconciled.
We begin by examining the validity of this contrast. For example, factors such as differential participation bias in the community surveys, incomparability of the HIV-1 and mortality indicators, and confounding influences on mortality, could result in conflicting gender differentials in HIV-1 seroprevalence and adult mortality.
In the second part of the paper, we use mathematical models to illustrate how factors such as the underlying pattern of sexual behaviour, higher rates of male-to-female than female-to-male heterosexual transmission, and variations in the length of the survival period after HIV-1 infection by age at infection, could lead to a period of higher female seroprevalence but lower female adult mortality.
An illustrative case study based on data from Zimbabwe is presented and the implications of our findings for national HIV-1 surveillance and the demographic impact of HIV-1 epidemics are discussed.