HIV-1 subtype C is not associated with higher risk of heterosexual HIV-1 transmission: a multinational study among HIV-1 serodiscordant couples.
Kahle, Erin;
Campbell, Mary;
Lingappa, Jairam;
Donnell, Deborah;
Celum, Connie;
Ondondo, Raphael;
Mujugira, Andrew;
Fife, Kenneth;
Mugo, Nelly;
Kapiga, Saidi;
+3 more...Mullins, James I;
Baeten, Jared M;
Partners in Prevention HSVHIV Transmission Study Team;
(2014)
HIV-1 subtype C is not associated with higher risk of heterosexual HIV-1 transmission: a multinational study among HIV-1 serodiscordant couples.
AIDS (London, England), 28 (2).
pp. 235-243.
ISSN 0269-9370
DOI: https://doi.org/10.1097/QAD.0000000000000024
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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.