HIV-1 subtype C is not associated with higher risk of heterosexual HIV-1 transmission: a multinational study among HIV-1 serodiscordant couples

AIDS. 2014 Jan 14;28(2):235-43. doi: 10.1097/QAD.0000000000000024.

Abstract

Background: HIV-1 subtype C has emerged as the most prevalent strain of HIV-1 worldwide, leading to speculation that subtype C may be more transmissible than other subtypes. We compared the risk of HIV-1 transmission for subtype C versus non-C subtypes (A, D, G and recombinant forms) among heterosexual African HIV-1 serodiscordant couples.

Methods: We conducted a nested case-control analysis using data from two prospective cohort studies of heterosexual HIV-1 serodiscordant couples from six countries in eastern and southern Africa. Cases (N = 121) included incident HIV-1 transmissions that were established as linked within the serodiscordant partnership by viral sequencing; controls (N = 501) were nontransmitting HIV-1-infected partners. Subtype was determined for partial env and gag genes. Multiple logistic regression controlled for age and gender of the HIV-1-nfected partner and self-reported unprotected sex. Plasma and genital HIV-1 RNA concentrations were compared between subtype C and non-C subtypes using generalized estimating equations.

Results: HIV-1 subtype C was not associated with increased risk of HIV-1 transmission compared with non-C subtypes: env adjusted odds ratio (adjOR) 1.14 [95% confidence interval (CI) 0.74-1.75, P = 0.6] and gag adjOR 0.98 (95% CI 0.63-1.52, P = 0.9). Plasma and genital HIV-1 RNA levels did not differ significantly for subtype C versus non-C.

Conclusion: In a geographically diverse population of heterosexual African HIV-1 serodiscordant couples, subtype C was not associated with greater risk of HIV-1 transmission compared with non-C subtypes, arguing against the hypothesis that subtype C is more transmissible compared with other common subtypes.

Publication types

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

MeSH terms

  • Adult
  • Africa, Eastern
  • Africa, Southern
  • Case-Control Studies
  • Cohort Studies
  • Disease Transmission, Infectious*
  • Family Characteristics
  • Female
  • Genotype
  • HIV Infections / transmission*
  • HIV Infections / virology*
  • HIV-1 / classification*
  • HIV-1 / genetics*
  • HIV-1 / isolation & purification
  • Heterosexuality
  • Humans
  • Male
  • Prospective Studies
  • Risk Assessment
  • env Gene Products, Human Immunodeficiency Virus / genetics
  • gag Gene Products, Human Immunodeficiency Virus / genetics

Substances

  • env Gene Products, Human Immunodeficiency Virus
  • gag Gene Products, Human Immunodeficiency Virus