The efficiency of male-to-female and female-to-male sexual transmission of the human immunodeficiency virus: a study of 730 stable couples. Italian Study Group on HIV Heterosexual Transmission.
To compare the efficiency of male-to-female and female-to-male sexual transmission of human immunodeficiency virus (HIV), we studied 524 female partners of HIV-infected men and 206 male partners of HIV-infected women in 16 Italian clinical centers. All of the partners had had a sexual relationship with the index case lasting for at least 6 months and presented no other risk factor than sexual exposure to the HIV-infected partner. Among the 730 couples, 24% of the female partners were HIV positive, in comparison with 10% of the male partners. Using logistic regression analysis, including gender and controlling for condom use, frequency of intercourse, anal sex, partner's CD4+ cell count and clinical stage, sexually transmitted diseases, genital infections, and contraceptive use, we found that the efficiency of male-to-female transmission was 2.3 (95% confidence interval = 1.1-4.8) times greater than that of female-to-male transmission. Between-gender differences in the contact surfaces and the intensity of exposure to HIV during sexual intercourse are possible reasons for the difference in efficiency of transmission.
Department of Epidemiology and Medical Informatics, National Research Council, Milan, Italy.
A
A
Nicolosi
M L
ML
Corrêa Leite
M
M
Musicco
C
C
Arici
G
G
Gavazzeni
A
A
Lazzarin
D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology / Q000635:transmission; D000328:Adult; D016022:Case-Control Studies; D003267:Contraception; D018562:Disease Transmission, Infectious / Q000706:statistics & numerical data; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission*; D006801:Humans; D007558:Italy; D016015:Logistic Models; D008297:Male; D012307:Risk Factors; D017678:Sex Distribution; D012725:Sexual Behavior