Things have gotten better, surprisingly enough. Kate Kellers' Reuters article observes that there has been a steep decline.
British researchers said Zimbabwe’s epidemic was one of the biggest in the world until the rate of people infected with HIV almost halved, from 29 per cent of the population in 1997 to 16 per cent in 2007.
Their findings show that Zimbabweans have primarily been motivated to change their sexual behaviour because of increased awareness about AIDS deaths which heightened their fears of catching the human immunodeficiency virus (HIV) that causes it.
[. . .]
The United Nations AIDS program said last year that young people in Africa were starting to lead a “revolution” in HIV prevention and driving down rates of the disease by having safer sex and fewer sexual partners.
The Imperial College researchers found that in Zimbabwe, a change in attitudes towards numbers of sexual partners was helped by HIV/AIDS prevention programs, which were reinforced through mass media, church leaders and employers.
The poor economic situation in Zimbabwe from the early 2000s would also have driven down the number of concurrent partners a man could have, due to constraints on his wallet, they said.
The study in question goes into more detail, suggesting that exposure--through education and through personal experiences with the suffering and dying--was key.
During the 1990s, a wide range of prevention and information programs were implemented utilizing the national media along with school-, workplace-, and church-based activities, peer education, and other inter-personal communication interventions. Community-based activities were intensified following establishment of the National AIDS Council in the late 1990s. This range of broader HIV education and prevention programming could have had impact. Focus group and interview participants mentioned a number of prevention programs and awareness/education efforts and many reported that the “B” part of “ABC” was promoted by churches in particular and was “heard” by many community members yet no specific intervention was cited consistently.
One question arising from this review is why similarly high AIDS mortality and extensive coverage of HIV prevention programs (resulting in similarly high levels of reported condom use, early and large reductions in STI incidence, etc.) in several other countries in the region have not yet led to substantial declines in HIV prevalence (or multiple sexual partnerships). Our comparative analysis of eight southern African countries revealed few patterns of association. The HIV epidemic in Zimbabwe is somewhat older than in some other countries in the region, yet HIV prevalence has been declining markedly for over a decade now, which has not occurred to nearly the same extent, for example, in Malawi and Zambia (where HIV arrived even earlier). In addition to the severe economic decline, where Zimbabwe does stand out is in having high levels of both secondary education and marriage, especially in urban men, among whom the greatest level of behavior change evidently has occurred. It appears that this unique combination helped facilitate: 1) a clearer understanding and acceptance of how HIV is sexually transmitted (once such information became widely available through various AIDS education and prevention programs commencing in the early 1990s), as some studies of schooling levels and HIV determinants have suggested and 2) a greater ability to act upon “be faithful” messages, given the stronger marriage pattern in Zimbabwe than that in neighboring countries also having relatively well-educated populations, such as Botswana and South Africa.
In addition, national survey data suggest that between the mid-1990s and the early 2000s, Zimbabweans increasingly received information about AIDS from their friends, churches, and other inter-personal (as compared to official media) sources. A similar pattern has been linked to behavior change in Uganda. Furthermore, the Zimbabwean government's early adoption of a home-based care policy may inadvertently have accelerated the process of behavior change. It has been hypothesized that, when people die at home, this direct confrontation with AIDS mortality is more likely to result in a tangible fear of death among family and friends than when patients are primarily cared for in clinical facilities, such as in Botswana.
Certainly HIV transmission in North American queer male communities halted altogether in the late 1980s when the mass dying of the infected began.