From Mwanza and Rakai to Beijing and Moscow? STD control and HIV prevention

STD treatment: how can it improve HIV prevention in the South?

BACKGROUND

Rates of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) and sexually transmitted diseases (STDs) are disproportionately high in the Southern United States. A high percentage of the population is black, and STD/HIV rates are particularly high among this group. Control and treatment of STDs offers promise as an HIV prevention strategy, and nowhere more than in the South.

OBJECTIVE

Identify those specific recommendations for control and treatment of STDs that available evidence indicates can reduce HIV transmission.

STUDY

Review of published literature.

RESULTS

Community trials produced inconsistent results but still suggest that STD treatment can reduce HIV transmission in the United States. Treatment of symptomatic STDs among those with HIV-infection should reduce HIV infectivity. There is as yet only limited evidence that STD treatment can reduce HIV susceptibility, although promising studies addressing herpes simplex virus are under way.

CONCLUSIONS

The unacceptably large racial disparities in STD rates must be addressed, symptomatic STDs among HIV-infected individuals treated, and syphilis prevention activities continued. Detection of unrecognized HIV infections among those seeking STD services should be a priority; identification of those with STDs and acute HIV infection may provide unique HIV prevention opportunities.

A community randomized controlled trial to investigate impact of improved STD management and behavioural interventions on HIV incidence in rural Masaka, Uganda: trial design, methods and baseline findings

OBJECTIVE

To describe study design, methods and baseline findings of a behavioural intervention alone and in combination with improved management of sexually transmitted diseases (STDs) aimed at reducing HIV incidence and other STDs.

DESIGN

A three-arm community randomized controlled trial (RCT) of 18 rural communities (approximately 96 000 adults) in SW Uganda. A standardized behavioural intervention was implemented in 12 communities (arms A and B) through community-based education, meetings and information leaflets. Six of these communities in addition received improved STD management through government and private health units (arm B). Arm C communities received routine government health services. Impact assessment was through three questionnaire and serological surveys of 750-1000 adults in each community at 18-24-month intervals. The primary outcome measure was HIV incidence and secondary measures were syphilis and herpes simplex virus type 2 incidence, prevalence of Neisseria gonorrhoea and Chlamydia trachomatis and sexual behaviour changes.

RESULTS

Approximately 15 000 adults (72% of eligible population) were enrolled at baseline. HIV baseline prevalence rates were 9-10% in all arms and demographic and behavioural characteristics and STD prevalence were also similar. In intervention communities, there were 391 995 attendance at 81 502 activities (6.1 per target adult), 164 063 leaflets distributed (2.6 per person) and 1 586 270 condoms (16.5 condoms per adult). In the STD communities a total of 12 239 STD cases (65% women) were seen over a 5-year period (7.7 per 100 adults/year).

CONCLUSION

This is the first community RCT of its type with a behavioural component. There is fair baseline comparability between study arms and process data suggest that interventions were adequately implemented.

Global impact of human immunodeficiency virus and AIDS

This review provides information on the epidemiology, economic impact, and intervention strategies for the human immunodeficiency virus (HIV)/AIDS pandemic in developing countries. According to the World Health Organization and the Joint United Nations Programme on HIV/AIDS (UNAIDS) at the end of 1999, an estimated 34.3 million people were living with HIV/AIDS. Most of the people living with HIV, 95% of the global total, live in developing countries. Examples of the impact of HIV/AIDS in Africa, Asia, Latin America, the Caribbean, and the Newly Independent States provide insight into the demographics, modes of exposure, treatment and prevention options, and the economic effect of the epidemic on the global community. The epidemic in each region of the world is influenced by the specific risk factors that are associated with the spread of HIV/AIDS and the responses that have evolved to address it. These influences are important in developing HIV/AIDS policies and programs to effectively address the global pandemic.

Complementary hypothesis concerning the community sexually transmitted disease mass treatment puzzle in Rakai, Uganda

OBJECTIVES

To study the dynamics of a mass treatment programme for sexually transmitted diseases (STD) on prevalence of STD and HIV incidence in order to help explain the results of the STD mass treatment community trial in Rakai, Uganda.

METHODS

The analysis is based on simulations of STD mass treatment interventions using a deterministic model describing the course of STD and HIV transmission over time and incorporating demographic, biological and behavioural parameters. The mass intervention modelled mimics that used in the Rakai community trial.

RESULTS

Mass treatment decreases STD prevalence to a very low level compared with baseline but is unsuccessful at eradicating the infection. STD prevalences return to baseline fairly rapidly after each round of mass treatment. Under different realistic scenarios, the fraction of HIV cases prevented by STD mass treatment assuming uniform 80% coverage of high- and low-risk groups, over the 20-month period following the first round of treatment, was greater than 35%. If, however, differential coverage is assumed, for example that while the total coverage is still 80%, only 40 or 25% of those at high risk are treated, the HIV preventable fraction is reduced, to 19 and 15% respectively (undetectable given the statistical power of the study). The tremendous impact of differential coverage can also be observed even in the early stage of the HIV epidemic.

CONCLUSIONS

In the Rakai trial, mass treatment may have had an effect, although transient, on all STD prevalences, which could have had positive repercussions for HIV incidence. This modelling exercise suggests that although an 80% coverage appears high, the differential coverage of low- and high-risk populations may seriously impair our ability to test the STD-HIV interaction hypothesis.