TY - JOUR
T1 - Probability of HIV-1 transmission per coital act in monogamous, heterosexual, HIV-1-discordant couples in Rakai, Uganda
AU - Gray, Ronald H.
AU - Wawer, Maria J.
AU - Brookmeyer, Ron
AU - Sewankambo, Nelson K.
AU - Serwadda, David
AU - Wabwire-Mangen, Fred
AU - Lutalo, Tom
AU - Li, Xianbin
AU - VanCott, Thomas
AU - Quinn, Thomas C.
N1 - Funding Information:
We thank Andre Nahmias (Emory University, Atlanta, GA, USA) for the HSV-2 assays, and S K Sempalla (Director, Uganda Virus Research Institute) for his support. The study was supported by grants RO1 AI34826 and RO1 AI3426S from the National Institute of Allergy and Infectious Diseases; grant 5P30HD06826 from the National Institute of Child Health and Development; grant 5D43TW00010 from the Fogarty Foundation; the US National Institutes of Health; the World Bank STI Project, Uganda; and the GlaxoWellcome Foundation.
PY - 2001/4/14
Y1 - 2001/4/14
N2 - Background: The probability of HIV-1 transmission per coital act in representative African populations is unknown. We aimed to calculate this probability overall, and to estimate how it is affected by various factors thought to influence infectivity. Methods: 174 monogamous couples, in which one partner was HIV-1 positive, were retrospectively identified from a population cohort in Rakai, Uganda. Frequency of intercourse and reliability of reporting within couples was assessed prospectively. HIV-1 seroconversion was determined in the uninfected partners, and HIV-1 viral load was measured in the infected partners. Adjusted rate ratios of transmission per coital act were estimated by Poisson regression. Probabilities of transmission per act were estimated by log-log binomial regression for quartiles of age and HIV-1 viral load, and for symptoms or diagnoses of sexually transmitted diseases (STDs) in the HIV-1-infected partners. Results: The mean frequency of intercourse was 8.9 per month, which declined with age and HIV-1 viral load. Members of couples reported similar frequencies of intercourse. The overall unadjusted probability of HIV-1 transmission per coital act was 0.0011 (95% CI 0.0008-0.0015). Transmission probabilities increased from 0.0001 per act at viral loads of less than 1700 copies/mL to 0.0023 per act at 38 500 copies/mL or more (p=0.002), and were 0.0041 with genital ulceration versus 0.0011 without (p=0.02). Transmission probabilities per act did not differ significantly by HIV-1 subtypes A and D, sex, STDs, or symptoms of discharge or dysuria in the HIV-1-positive partner. Interpretation: Higher viral load and genital ulceration are the main determinants of HIV-1 transmission per coital act in this Ugandan population.
AB - Background: The probability of HIV-1 transmission per coital act in representative African populations is unknown. We aimed to calculate this probability overall, and to estimate how it is affected by various factors thought to influence infectivity. Methods: 174 monogamous couples, in which one partner was HIV-1 positive, were retrospectively identified from a population cohort in Rakai, Uganda. Frequency of intercourse and reliability of reporting within couples was assessed prospectively. HIV-1 seroconversion was determined in the uninfected partners, and HIV-1 viral load was measured in the infected partners. Adjusted rate ratios of transmission per coital act were estimated by Poisson regression. Probabilities of transmission per act were estimated by log-log binomial regression for quartiles of age and HIV-1 viral load, and for symptoms or diagnoses of sexually transmitted diseases (STDs) in the HIV-1-infected partners. Results: The mean frequency of intercourse was 8.9 per month, which declined with age and HIV-1 viral load. Members of couples reported similar frequencies of intercourse. The overall unadjusted probability of HIV-1 transmission per coital act was 0.0011 (95% CI 0.0008-0.0015). Transmission probabilities increased from 0.0001 per act at viral loads of less than 1700 copies/mL to 0.0023 per act at 38 500 copies/mL or more (p=0.002), and were 0.0041 with genital ulceration versus 0.0011 without (p=0.02). Transmission probabilities per act did not differ significantly by HIV-1 subtypes A and D, sex, STDs, or symptoms of discharge or dysuria in the HIV-1-positive partner. Interpretation: Higher viral load and genital ulceration are the main determinants of HIV-1 transmission per coital act in this Ugandan population.
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U2 - 10.1016/S0140-6736(00)04331-2
DO - 10.1016/S0140-6736(00)04331-2
M3 - Article
C2 - 11323041
AN - SCOPUS:0035857959
SN - 0140-6736
VL - 357
SP - 1149
EP - 1153
JO - Lancet
JF - Lancet
IS - 9263
ER -