HIV prevalence in Uganda declined in the 1990s by 70%, thanks to community mobilisation and risk-avoidance at a population level, according to a study published in the April 30th edition of Science. In particular, investigators from Cambridge University attribute the dramatic decline in HIV prevalence in Uganda to a later average age of sexual debut, and a reduction in the number of sexual partners, backed by a consistent message from the Ugandan government and high levels of awareness communicated by word of mouth. "The outcome was equivalent to a highly effective vaccine," the researchers say.
An article and editorial in the BMJ earlier this month (see link below for aidsmap news story), argued that partner reduction was a key factor, but overlooked other aspects of HIV prevention.
The Cambridge population scientists found information about HIV was disseminated by word-of-mouth through social and familial networks and awareness of the consequences of HIV infection was increased as the overwhelming majority of the population knew somebody with the disease.
In 1994, data from HIV prevalence studies amongst young pregnant women in Uganda suggested that there had been a substantial decrease in HIV prevalence in Uganda. These data were viewed with caution and confusion.
However, studying HIV rates amongst younger pregnant women, the Cambridge investigators established that HIV incidence was declining in Uganda by the late 1980s, and that by 1995 there had been significant declines in HIV prevalence, particularly amongst younger women. The investigators established that HIV prevalence in pregnant women aged 15-24 peaked at 21% in 1991, but by 1998 had fallen to 9.7%, a decline of 54%. A further decline in HIV prevalence in this population of 6% was seen in 2000. These declines were seen in both urban and rural areas.
Data from the Ugandan capital, Kampala, showed that HIV prevalence declined by 75% in 15-20 year olds, with a fall of 60% in the 20-24 age group.
When the investigators compared these data with those from neighbouring countries (Kenya, Malawi, Zambia), they found that declines in HIV prevalence were unique to Uganda.
An analysis of population-based surveys of HIV risk conducted in 1989 and 1995 showed that there had been an important reduction in some key HIV risk behaviours between these two dates, in particular an increased age of sexual debut, a reduction in numbers of sexual partners, and increased use of condoms with both regular and non-regular partners.
In particular, the investigators highlight that between 1989 and 1995 there was a 60% reduction in the number of persons reporting casual sex in the previous year. The number of individuals reporting casual sex in neighbouring countries did not change substantially between these dates. However, comparable numbers of Ugandans and individuals living in neighbouring countries reported condom use. This suggested to the investigators that “reduction in sexual partners and abstinence among unmarried sexually inexperienced youth … rather than condom use, are the relevant factors in reducing HIV incidence.”
The investigators also found that there was a high level of knowledge about HIV in the Ugandan population, with personal channels of communication being the main source of information. In Uganda, 82% of women were aware of HIV, compared to only 40-65% of women in neighbouring countries. Ugandans also had high levels of personal contact with individuals with AIDS. By 1995, 91.5% of Ugandan men and 86.4% of Ugandan women said they knew somebody with AIDS. This compared to between 68- 71% in Malawi and Kenya, and in 2002, less than 50% of the South African population knew a person with HIV.
“This suggests that a credible communication of alarm and advice had taken root in discussions in social networks” to a greater extent in Uganda than other countries, the investigators suggest.
The Ugandan government’s initial response to HIV is also highlighted by the investigators as being key to the country’s HIV prevention efforts. Prevention messages were simple and included a clear warning about the danger of HIV, and basic advice about behavioural change – “zero grazing”, in other words, “faithfulness to one partner”. More sophisticated messages about condom use were not part of the initial strategy and came later, after reductions in HIV incidence had already been achieved.
“The current practice of scaling up biomedical and risk-reduction HIV prevention elements may not reduce sexual transmission at the population level,” say the authors, who point out that the bulk of the reduction in HIV incidence and prevalence occurred before widespread condom promotion, voluntary counselling and testing and sexually transmitted infection treatment began.
Comparisons are made by the investigators between the success of Uganda and the early community mobilisation and population risk avoidance seen in gay men in the US and Europe in response to HIV in the 1980s and early 1990s. To ensure that the successes of Uganda are replicated elsewhere, the investigators conclude that there is a need for a “shift in strategic thinking on health policy and HIV/AIDS, with greater attention to epidemiological intelligence and communications to mobilise risk avoidance.”
Further information on this website
Stoneburner RL et al. Population-level HIV declines and behavioural risk avoidance in Uganda. Science: 304: 714-718, 2004.