Rates of HIV-1 transmission per coital act, by stage of HIV-1 infection, in Rakai, Uganda

Maria J. Wawer, Ronald H. Gray, Nelson K. Sewankambo, David Serwadda, Xianbin Li, Oliver Laeyendecker, Noah Kiwanuka, Godfrey Kigozi, Mohammed Kiddugavu, Thomas Lutalo, Fred Nalugoda, Fred Wabwire-Mangen, Mary P. Meehan, Thomas C. Quinn

Research output: Contribution to journalArticlepeer-review

Abstract

Background. We estimated rates of human immunodeficiency virus (HIV)-1 transmission per coital act in HIV-discordant couples by stage of infection in the index partner. Methods. We retrospectively identified 235 monogamous, HIV-discordant couples in a Ugandan population-based cohort. HIV transmission within pairs was confirmed by sequence analysis. Rates of transmission per coital act were estimated by the index partner's stage of infection (recent seroconversion or prevalent or late-stage infection). The adjusted rate ratio of transmission per coital act was estimated by multivariate Poisson regression. Results. The average rate of HIV transmission was 0.0082/coital act (95% confidence interval [CI], 0.0039-0.0150) within ∼2.5 months after seroconversion of the index partner; 0.0015/coital act within 6-15 months after seroconversion of the index partner (95% CI, 0.0002-0.0055); 0.0007/coital act (95% CI, 0.0005-0.0010) among HIV-prevalent index partners; and 0.0028/coital act (95% CI, 0.0015-0.0041) 6-25 months before the death of the index partner. In adjusted models, early- and late-stage infection, higher HIV load, genital ulcer disease, and younger age of the index partner were significantly associated with higher rates of transmission. Conclusions. The rate of HIV transmission per coital act was highest during early-stage infection. This has implications for HIV prevention and for projecting the effects of antiretroviral treatment on HIV transmission.

Original languageEnglish (US)
Pages (from-to)1403-1409
Number of pages7
JournalJournal of Infectious Diseases
Volume191
Issue number9
DOIs
StatePublished - May 1 2005

ASJC Scopus subject areas

  • Immunology and Allergy
  • Infectious Diseases

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