In the ten years leading to 2007, Zimbabwe saw a dramatic fall in the number of people infected with HIV. New research published in ‘PLoS Medicine’ has shed light on how mass social change driven by greater awareness of AIDS-related deaths led to this unexpected downturn, providing important lessons in the fight against the disease for the rest of Africa.
The HIV epidemic in Zimbabwe was one of the biggest in the world: in 1997, an estimated 29 per cent of adults were thought to be HIV positive. Yet, against a background of massive social, political and economic disruption in the country, this number had fallen to 16 per cent by 2007.
An international team of researchers studying this fall have now shown that people in Zimbabwe were primarily motivated to change their sexual behaviour because of improved public awareness of AIDS deaths and a subsequent fear of contracting the virus. Other important drivers included the influence of education programmes that have shifted people's attitudes towards having multiple concurrent sexual partners in extramarital, commercial and casual relations and that have made condom use for casual sex more acceptable.
Professor Simon Gregson from Imperial College London, senior investigator on the study, said: "Given the continuing, and worrying, trend for high HIV infection rates in many sub-Saharan African countries, we felt it was important to understand why the disease has taken a such a dramatic downturn in Zimbabwe. Very few other countries around the world have seen reductions in HIV infection, and of all African nations, Zimbabwe was thought least likely to see such a turnaround."
Dr Timothy Hallett, also from Imperial College London, added: "The HIV epidemic is still very large, with more than one in ten adults infected today. We hope that Zimbabwe - and other countries in southern Africa - can learn from these lessons and strengthen programs to drive infections down even further."
The researchers say a change in peoples' attitudes towards their numbers of partners was helped by HIV prevention programs organised by the National AIDS Council through the mass media and church-based, workplace-based and other interpersonal communication activities.
The unfavourable economic situation in Zimbabwe from the early 2000s would also have meant that men had less money and consequently fewer concurrent partners. However, this occurred after behaviour had begun to change and would have been unlikely to have altered attitudes towards infection.
Other underlying factors found to distinguish Zimbabwe from neighbouring countries, and which may have contributed to the changes in behaviour, included its well-educated population and strong traditions of marriage.
The researchers reached their conclusions after investigating the results of studies from the past 20 years, which were also considered at a national public health meeting in the Zimbabwean capital, Harare, in 2008. Several other factors affecting HIV infection were also discussed, including the age at which people first engaged in sexual behaviour, the introduction of HIV testing and counselling services, and transmission of the virus through means other than sex (such as blood transfusion and needle sharing). These were ruled out, however, following close examination of the medical and programme evidence.
The results of this study were extensively and openly debated at the national meeting in Zimbabwe, where attendees reached a 'clear consensus' about the legitimacy of the findings. The researchers hope that by making the data available more widely, the conclusions of the study can be judged by other policy makers in the international community and that a clear message can be agreed about the factors driving a decline in HIV.
Some of the studies upon which this paper is based were funded by the United Nations Population Fund, which provided some logistical support, as well as helping with coordination between the studies. The United Nations HIV-AIDS Program and the Zimbabwean Ministry for Health and Child Welfare sponsored this study, along with funding from the Wellcome Trust.