AEGiS-15IAC: Impact of a longitudinal research study on risk behaviour and HIV-incidence in a high-risk cohort of 600 women in southern Tanzania.

15th International AIDS Conference

Bangkok, Thailand - July 11-16, 2004

Impact of a longitudinal research study on risk behaviour and HIV-incidence in a high-risk cohort of 600 women in southern Tanzania.

Int Conf AIDS 2004 Jul 11-16; 15:(abstract no. TuOrC1203)

Hoffmann O, Wolff B, Maboko L, Mmbando D, Samky E, McCutchan F, Todd J, Zaba B, Hoelscher M
Department of Infectious Diseases and Tropical Medicine, University of Munich and London School of Hygiene and Tropical Medicine, Munich/London, Germany

Introduction: The HISIS Study, established in 2000, has an open cohort design for 600 female bar and guest-house workers followed up at three-monthly intervals for 30 months, to learn about socio-demographic, virologic and immunologic correlates of HIV-1 infection and HIV-superinfection in high-risk occupational groups.

METHODS: During each study visit women were tested for HIV and interviewed face-to-face about sexual behaviour. Free medical check ups were provided, including treatment for STI, health education, and HIV counselling.

RESULTS: Initial HIV-1 prevalence in the cohort was 68%. After 30 months, 34 out of 192 initially HIV negative study participants sero-converted (cumulative incidence 18%). 24 and 7 participants respectively sero-converted in the first year (annual incidence 14 per 100 pyr) and in the second year (annual incidence 4 per 100 pyr). Risk-factors for HIV infection relating to casual sexual partners fell during the 30 month follow up. Fewer participants had casual sex partners in each three month interval (53% at enrolment versus 34% at 30 months) whilst consistent condom use with casual partners rose from 15% to 44%. The number of long-term partners remained stable at a high level (85% versus 93%) and consistent condom use with those partners remained low (13% versus 18%). The number of participants who left the high risk occupations by 30 months reached 39%. Discussion: Initial HIV prevalence was extremely high as was HIV-incidence in the first year. Reported behaviour with the main partners did not change over time. The subsequent reduction in HIV incidence might be explained by changes in risk behaviour with casual partners and the remarkable withdrawal from work in high risk places. A carefully designed research study can reduce HIV infection risks in such occupational groups.

Keywords: AEGIS, HIV, Acquired Immunodeficiency Syndrome, Incidence, Risk-Taking, HIV Seropositivity, Longitudinal Studies, HIV Infections, Sexual Behavior, Risk Factors, Prevalence, Research, HIV Seroprevalence, Biomedical Research, HIV-1, Tanzania, Humans, Female, epidemiology

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TuOrC1203