HIV seroconversion among factory workers in Harare: who is getting newly infected?

Zimbabwe, like other countries in sub-Saharan Africa, is experiencing a rapidly growing HIV/AIDS epidemic. It is crucial to determine risk events and socio-demographic characteristics associated with incident infections in order to tailor prevention messages accordingly. A cohort was established among factory workers with the objectives of estimating HIV incidence, seroprevalence, correlates of infection and subsequently evaluating the impact of prevention interventions.

40 factories in Harare, Zimbabwe.

HIV seroindicence [total new infections over person time (years) follow up] was estimated in a longitudinal cohort of male factory workers before and during a randomised peer education intervention. Correlates of seroconversion were identified using Cox regression analysis.

Of 2,992 subjects enrolled there were 129 seroconversions during 1993 to 1996 follow up, yielding a 2.96 per 100 person year (PY) seroconversion incidence (95% CI = 2.47 to 3.52). Reporting a genital ulcer during follow up (Hazard ratio [HR] = 4.9, p = 0.001) having multiple sexual partners (HR = 1.9, p = 0.04), having a urethral discharge (HR = 2.1, p = 0.001), being single (HR = 2.3, p = 0.001), widowed or married but not residing with wife were independent factors significantly associated with risk of HIV seroconversion.

Incidence of HIV identified in this economically productive sector is unacceptably high, and, disturbingly, is increasing in some age groups. Although the impact of the present intervention remains to be evaluated, the high incidence of HIV infection, points to the need for a more aggressive prevention effort in the general population.