The relatively common practice in many African countries of having ongoing relationships with two or three partners at the same time, has led researchers to explore concurrency as a possible explanation for why parts of the continent have been so hard hit by HIV.

While most Africans report similar numbers of partners over a lifetime as their Western counterparts, having long-term simultaneous relationships is thought to put them at much higher risk from HIV by placing them in overlapping sexual networks that serve as ‘€œa superhighway for the rapid spread of HIV’€, as scientist and author Helen Epstein, puts it in her book, The Invisible Cure.

As studies from around Africa have provided more evidence to support the theory, it has gradually gained currency with epidemiologists and public health experts. In recent years multiple concurrent partnerships (MCPs) have become widely accepted as one of the main drivers of HIV epidemics in southern and eastern Africa and prevention programmes have been designed accordingly.

But not everyone in the scientific community accepts the theory. Its main proponents ‘€“ Daniel Halperin, Helen Epstein, Martina Morris and Timothy Mah ‘€“ have come under fire from several critics in the past year who argue that there is insufficient evidence to support the focus on MCPs.

The latest installment in the debate arrived in September in the form of an article in the Journal of the International AIDS Society by Larry Sawers and Eileen Stillwaggon, both United States-based economists, that minutely reviews the evidence to support the concurrency hypothesis and finds it either lacking or contradictory.

The authors refute the idea that concurrency is more prevalent in Africa than elsewhere, arguing that the mathematical model used to validate the hypothesis was seriously flawed by over-estimates of the frequency of sexual contact and the risk of contracting HIV per sexual encounter among other things.

They insist there must be other explanations for Africa’€™s extraordinary HIV epidemics, such as high levels of bacterial, viral and parasitic infections in the region that make people more vulnerable to HIV and more likely to transmit it. They also suggest that the role of blood exposures from unsterilized syringes, circumcision and dental procedures deserves more attention.

Finally, and most controversially, Sawers and Stillwaggon call for an end to sexual behaviour research in Africa and ‘€œthe continued use of financial and human resources to prove Western preconceptions about African sexuality’€.

The Response

Speaking to IRIN/PlusNews over the phone from Boston where he is a lecturer on International Health at the Harvard School of Public Health, Halperin described the article as ‘€œvery damaging potentially’€ and compared Sawers and Stillwaggon’€™s approach as similar to that used by AIDS and climate change denialists.

Halperin pointed out that the types of parasitic diseases mentioned by Sawers and Stillwaggon as possible alternative reasons for African HIV epidemics, such as schistosomiasis and malaria are not common in many of the countries that have the highest HIV prevalence rates.

‘€œIt seems pretty compelling for someone who’€™s not up on all the literature,” he said. “But it’€™s actually preposterous what they’€™re suggesting ‘€“ that non-sexual transmission is the main reason for high HIV in Africa.

“If you go out to shebeens [informal taverns in South Africa] and talk to people about sexual behaviour, I’€™m sure you’€™ll find out what’€™s going on. Everyone will tell you that strict mutual monogamy is the exception not the rule.”

In response to criticisms of the model that was originally used to validate the concurrency hypothesis, Epstein said it was not designed to be realistic but to answer a simple question about the role of over-lapping versus serial relationships in the spread of HIV. In the 13 years since the model was developed, she added, other researchers have looked at data from real populations and found that concurrency did explain a major part of epidemics, but that Sawers and Stillwaggon had not included those studies in their review.

“This isn’t a balanced approach,” she told IRIN/PlusNews. “I think there definitely needs to be debate about anything that has strong implications for programming because we really don’€™t have a good handle on prevention in Africa, but I think we really need better scholarship.”

Epstein added that the role of concurrent partnerships as a driver of HIV had only become a focus of HIV/AIDS efforts in Africa in the past couple of years. “We’€™ve really just arrived at this new understanding of what’€™s going on and we need to give it a chance to work.”

Like Halperin, she worried that the debate could influence the types of programmes that donors choose to fund at a time when competition for funding is particularly fierce. “Donors already are backing away from behavioural approaches to HIV and towards taking a totally biomedical approach…and I think that would be a tragedy,” she said.

“Red herring”?

Programme implementers on the ground are mostly oblivious to or perplexed by the academic debate. “The merits of programmes need to be looked at for their merits and not dictated by ideological points of view,” said Richard Delate, programme director for Johns Hopkins Health and Education in South Africa (JHHESA) which has been involved in a number of campaigns with a MCP focus all of which Delate insisted were evidence-based.

Dr Sue Goldstein, a researcher with the South Africa-based Soul City Institute for Health and Development Communication described the debate as “a red herring”.

“We all tend to agree with the UNAIDS call for combination prevention which really looks at biomedical, social and behaviour change together to try and address a massive epidemic,” she told IRIN/PlusNews.

She nevertheless endorsed the MCP focus of her organization’s OneLove campaign, which has rolled out in nine southern African countries since 2008. “Previously, we’€™d really pushed condoms and we kind of felt it wasn’€™t working so we did want to push MCPs, but we looked at underlying issues ‘€“ cultural and social, which in the end are what are going to change people’€™s behaviour,” she explained. “Our OneLove campaign has been exceptionally well received and people are really keen to start these discussions.”

According to Sawers, however, his criticism of the concurrency theory has already gone beyond the level of academic debate. Responding to IRIN/PlusNews by email from Washington DC, where he teaches economic development at American University, he said that he and his co-author had just returned from Nigeria where they met with the National Agency for the Control of AIDS and the local office of the U.S. Centers for Disease Control and Prevention (CDC).

“We found an openness and excitement about our ideas, and an eagerness to implement concrete actions based on our ideas,” he wrote. “What we heard from many people…in Nigeria is that a well-reasoned and carefully argued proposal to donors is likely to be funded.”

He added that without “effectively dismissing” the concurrency argument first, he had no doubt their reception would have been less enthusiastic.

This feature is used with permission from IRIN/PlusNews  –  www.plusnews.org