Incidence of HIV infection in stable sexual partnerships: a retrospective cohort study of 1802 couples in Mwanza Region, Tanzania.
OBJECTIVE
To describe the dynamics of HIV transmission in stable sexual partnerships in rural Tanzania.


METHODS
Retrospective cohort study nested within community-randomized trial to investigate the impact of a sexually transmitted disease treatment program.


METHODS
A cohort of 1802 couples was followed up for 2 years, with the HIV status of each couple assessed at baseline and follow-up.


RESULTS
At baseline, 96.7% of couples were concordant-negative, 0.9% were concordant-positive, 1.2% were discordant with the male partner being HIV-positive, and 1.2% were discordant with the female partner being HIV-positive. Individuals living with an HIV-positive partner were more likely to be HIV-positive at baseline (women: odds ratio [OR] = 75.7, 95% confidence interval [CI]: 33.4-172; men: OR = 62.4, CI: 28.5-137). Seroincidence rates in discordant couples were 10 per 100 person-years (py) and 5 per 100 py for women and men, respectively (rate ratio [RR] = 2.0, CI: 0.28-22.1). In concordant-negative couples, seroincidence rates were 0.17 per 100 py in women and 0.45 per 100 py in men (RR = 0.38, CI: 0.12-1.04). Individuals living in discordant couples were at a greatly increased risk of infection compared with individuals in concordant-negative couples (RR = 57.9, CI: 12.0-244 for women; RR = 11.0, CI: 1.2-47.5 for men).


CONCLUSIONS
Men were more likely than women to introduce HIV infection in concordant-negative partnerships. In discordant couples, incidence in HIV-negative women was twice as high as in men. HIV-negative individuals in discordant partnerships are at high risk of infection, and preventive interventions targeted at such individuals are urgently needed.
Hugonnet
Stéphane
S
London School of Hygiene and Tropical Medicine, London, UK.
Mosha
Frank
F
Todd
James
J
Mugeye
Kokugonza
K
Klokke
Arnoud
A
Ndeki
Leonard
L
Ross
David
D
Grosskurth
Heiner
H
Hayes
Richard
R
D000328:Adult; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D015658:HIV Infections / Q000453:epidemiology*; D006679:HIV Seropositivity / Q000453:epidemiology; D006801:Humans; D008297:Male; D016017:Odds Ratio; D012189:Retrospective Studies; D012307:Risk Factors; D012747:Sexual Partners; D013636:Tanzania / Q000453:epidemiology