Heterosexual Transmission of Human Immunodeficiency Virus (HIV) in Northern California: Results from a Ten-year Study

Abstract

To examine rates of and risk factors for heterosexual transmission of human immunodeficiency virus (HIV), the authors conducted a prospective study of infected individuals and their heterosexual partners who have been recruited since 1985. Participants were recruited from health care providers, research studies, and health departments throughout Northern California, and they were interviewed and examined at various study clinic sites. A total of 82 infected women and their male partners and 360 infected men and their female partners were enrolled. Over 90% of the couples were monogamous for the year prior to entry into the study; < 3% had a current sexually transmitted disease (STD). The median age of participants was 34 years, and the majority were white. Over 3,000 couple-months of data were available for the follow-up study. Overall, 68 (19%) of the 360 female partners of HIV-infected men (95% confidence interval (CI) 15.0-23.3%) and two (2.4%) of the 82 male partners of HIV-infected women (95% CI 0.3-8.5%) were infected. History of sexually transmitted diseases was most strongly associated with transmission. Male-to-female transmission was approximately eight-times more efficient than female-to-male transmission and male-to-female per contact infectivity was estimated to be 0.0009 (95% CI 0.0005-0.001). Over time, the authors observed increased condom use (p < 0.001) and no new infections. Infectivity for HIV through heterosexual transmission is low, and STDs may be the most important cofactor for transmission. Significant behavior change over time in serodiscordant couples was observed.

Virologic and Immunologic Determinants of Heterosexual Transmission of Human Immunodeficiency Virus Type 1 in Africa

“…Two early studies reported that infected men were more likely to transmit HIV to their partners than infected women. 40,41 These results fit "common sense" notions that women were more susceptible since a large inoculum of infected seminal fluid was deposited on a large susceptible surface area that may be abraded during sexual activity. In contrast, men were exposed to a relatively smaller volume of infected vaginal fluids on a less friable epithelial surface, for relatively shorter periods of time.…”

Women, Inequality, and the Burden of HIV

“…The mucosal lining of the vagina provides a more permeable membrane than does the penile shaft, and microlesions in the vaginal mucosa caused by other sexually transmitted infections permit increased viral penetration. 3 However, the spread of HIV among women has sociopolitical as well as biologic roots: it arises from the inequity between the sexes, societies' class structures, and the inaccessibility of health care. In many societies, educational and employment opportunities for women are limited.…”

Trajectoires de vie et prises de risques chez les femmes usagères de drogues

“…La relation étroite entre consommation de produits et sexualité tend donc à accentuer l'exposition au risque chez les femmes, les effets psychoactifs des produits pouvant diminuer le niveau de vigilance et la dépendance au conjoint, réduisant également leur capacité de négociation quant à la protection des rapports sexuels. Cette vulnérabilité sociale s'ajoute à une vulnérabilité d'ordre biologique, puisque la transmission du VIH est sept à neuf fois plus fréquente dans le cadre de l'exposition homme-femme que femme-homme [18]. De manière globale, les femmes usagères de drogues s'engagent donc plus dans des comportements à risque que les hommes, tant vis-à-vis des drogues que de la sexualité [2,19].…”