High Transmissibility During Early HIV Infection Among Men Who Have Sex With Men-San Francisco, California

J Infect Dis. 2015 Jun 1;211(11):1757-60. doi: 10.1093/infdis/jiu831. Epub 2014 Dec 26.


We estimate the relative transmission rate in early versus later infection among men who have sex with men (MSM) in San Francisco, California, by studying the characteristics of a sample of transmitters, recruited through newly diagnosed, recently infected MSM between 1996 and 2009. Of 36 transmitters identified, 9 were determined on the basis of testing history and serologic testing to have been recently infected. The unadjusted odds ratio of transmitting during early infection was 15.2 (95% confidence interval [CI], 6.3-33.4; P < .001); the odds ratio was 8.9 (95% CI, 4.1-19.4) after adjustment for self-reported antiretroviral treatment. This high transmissibility could be due to both high infectiousness and high rates of sex partner change or concurrent partnerships.

Keywords: HIV; San Francisco; early infection; men who have sex with men; transmission rate.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • HIV Infections / epidemiology*
  • HIV Infections / transmission*
  • Homosexuality, Male / statistics & numerical data*
  • Humans
  • Male
  • Odds Ratio
  • Retrospective Studies
  • San Francisco / epidemiology