Injections, alcohol, major risk factors for HIV infection in women in Tanzania prevention trial

Receiving injections outside clinic settings and increased alcohol use emerged as major risk factors for HIV infection among women taking part in an HIV prevention trial in Tanzania, according to the findings of a study published in the January 28^th edition of AIDS.

The study was a prospective randomised trial conducted in Tanzania. It was done to evaluate the impact of herpes treatment on HIV incidence among women in high-risk settings and was led by Dr Deborah Watson-Jones of London School of Hygiene and Tropical Medicine.

To recruit participants, the investigators interviewed women aged 16 to 35 years who worked in bars, guesthouses and similar settings in 19 communities in Tanzania. The prospective participants were tested for Herpes simplex virus type 2 (HSV-2) and HIV. They were then asked to attend a review session after two to three months.

The researchers enrolled 821 HIV-negative women into the study and randomised 400 into the intervention arm and 421 into the placebo arm. The women in the intervention arm received four months’ supply of aciclovir (400mg in a twice-daily dose) to treat HSV-2. There were three-monthly follow-ups for a maximum of thirty months. The participants’ median age was 28 years and about 80% (659) of the women completed the study.

At review visits participants were offered pregnancy tests, family planning services, sexually transmitted infection (STI) screening and counselling, HIV voluntary counselling and testing (VCT), treatment for any medical problems, and free condoms. Vaginal and cervical specimens were collected at 6, 12, 24 and 30 months' visits and were tested for HIV and other STIs. Genital examinations were carried out on any participant who raised concerns about a potential sexually transmitted infection.

The investigators used the Cox proportional-hazards regression model to estimate the hazards ratio (the measure of how many cases of infection took place among intervention group members compared to the control group over the research period) for HIV infection.

Overall, sixty-three women became infected with HIV. There was no significant difference between placebo and intervention arms (hazard ratio = 1.01). The results showed that younger women (16 to 19 years) had higher HIV incidence (about 10 per 100 person-years) than older ones ([30-35 years], incidence of about 3 per 100 person-years).

The scientists did multivariate analyses looking at age-adjusted risk factors and found that increased alcohol consumption ([>30 drinks of alcohol per week], adjusted hazard ratio = 4.39), receiving injection outside the study clinic (adjusted hazard ratio = 3.45), having paid sex in the previous three months (adjusted hazard ratio = 1.85) and infection with gonorrhoea (adjusted hazard ratio = 3.62) were the leading risk factors for HIV infection. The investigators also found that length of stay at the site (

The investigators noted that their findings confirm what similar studies had shown regarding HIV infection risks associated with alcohol use, gonorrhoea infection, out-of-clinic injections and use of hormonal contraception in various parts of Africa. They said alcohol use was linked with increased risky sexual behaviours, violence and coercive sex as reported by similar studies in South Africa and Uganda.

The researchers also noted that most injections resulted from what they called "over-diagnosis" with malaria, common in sub-Saharan Africa, which has similar symptoms to seroconversion. This suggests increased risk of HIV infection if safe injection practices are not maintained, the researchers said.

However, the scientists noted they were not able to determine the independent effect of HSV-2 on HIV incidence and that their findings might have been limited by over-reliance on self-reported sexual behaviours.

The researchers concluded that there is a need for interventions that address the risks associated with alcohol use and to sustain control of sexually transmitted infections. They also stressed the need to target young women in the study population with prevention interventions.

The scientists noted that their findings were applicable to many women in similar occupational settings.

Lastly, the investigators recommend further studies on the impact of injections and hormonal contraception on HIV incidence in similar high-risk settings.