Samuel Clark

Africa: Epidemiology and Demography


I was born in Kenya and mostly lived in East Africa - Tanzania and Kenya - until I was almost sixteen. Consequently I identify as American and African, and I have oriented the bulk of my career toward research on topics that are important to Africa. Starting in graduate school I have worked continuously until now on a variety of epidemiology and demography studies in or related to Africa.

There are a number of themes that run through these studies: HIV, the epidemographic transition, effects of household composition on mortality, orphan mortality, and cause of death. Those without their own pages are described briefly below.


The HIV epidemic in Africa has killed millions of people and severely affected the lives of millions more. Because HIV is a sexually transmitted infection, it interacts with or affects both mortality and fertility, and consequently, population dynamics and age structure. Likewise, interventions that disrupt HIV transmission - e.g. condoms - also affect fertility and population dynamics. In my PhD I built a stochastic microsimulation model of an HIV epidemic in a population with realistic demography to understand how the epidemiology and demography of HIV interact. Following that I was co-PI of an HIV behavior and seroprevalence study at the Agincourt health and demographic surveillance (HDSS) site in South Africa and participated in a number of studies of the effects of HIV. An example is a study of circular labor migration during the HIV epidemic in South Africa; results are consistent with the idea that terminally ill migrant workers returned to their home villages to die.

Epidemographic Transition

The classic large change phases of both the epidemiological and demographic transitions are still underway in Africa. HIV has created a unique disruption in the traditional epidemiological transition, and fertility remains high and is falling more slowly than it did in many other world regions. There is a complex interaction between these things, and together with a number of colleagues - mostly Chodziwadziwa Kabudula and Brian Houle - I have done a number of studies investigating aspects of these intertwined transitions.

Effects of Household Composition on Mortality

Household composition - how many people of each type live with you - can affect survival, especially for young children. Health and demographic surveillance systems accumulate detailed information on who is living with who through time, and that data allows unusual, detailed investigations of the effects of household composition on mortality. Again mainly with colleagues Chodziwadziwa Kabudula and Brian Houle, I have contributed to a number of studies of this kind. Perhaps the most consequential is on orphan mortality, described on its own page.

Updated 2021-02-02