Contrary to conventional wisdom, scientific evidence proving that overlapping multiple sexual partners - concurrency - drives the HIV epidemic in sub-Saharan Africa is actually quite limited, Brown University researchers have concluded.
As a result, they say, far more research is needed to prove what has been a long-held assertion for close to 15 years - that the sexual practice of concurrency has accelerated the spread of HIV in Africa.
"People have just accepted at face value that this is the main thing that's driving the epidemic," said epidemiologist Mark Lurie, assistant professor community health and medicine. "But the evidence that concurrency is a major factor is very weak."
Lurie and co-author Samantha Rosenthal detail their argument in an upcoming issue of the journal AIDS and Behavior. The article is available online now. Rosenthal is a graduate student in public health at Brown.
Lurie and Rosenthal say there is no conclusive evidence that overlapping multiple sexual partners increases the size of an HIV epidemic, accelerates the speed at which the virus is transmitted or makes HIV more persistent in a given population. They drew their conclusion by looking at previous studies that examined concurrency in any way.
The reason, they say, is that HIV epidemics can't be explained by a single variable. A number of factors are more likely, with some factors more important in some geographic areas than others.
"The studies you need to prove causality don't exist," Lurie said. "None of those studies have been done."
The researchers don't dispute the notion that concurrent sexual relationships could "theoretically" play a major role driving HIV transmission through networks of people. But before this can be proven true, Lurie and Rosenthal say, a number of research initiatives are needed including: