Viral control is more prevalent in infected partners in HIV-serodiscordant couples compared with individuals with HIV who are not in a stable discordant relationship, potentially as a result of behavioral and biologic HIV resistance factors in discordant couples, according to study results published in PLOS One.1

HIV-serodiscordant couples, defined as one partner being positive for HIV and the other negative, have been identified as a priority population for preventing HIV transmission. However, studies have shown that serodiscordant couples that remain so beyond an initial period are more likely to have characteristics that reduce the risk for transmission such as behavioral factors (eg, high condom use), host genetic factors, or viral factors (eg, poor replicative fitness).2-8 It is unknown, however, whether there is a biologic basis contributing to reduced infectiousness of the infected partner.

Therefore, researchers followed 2 cohorts of Kenyan women with HIV, one of which was comprised of 296 women in discordant couples and the other of 220 women who were sex workers.1 The researchers found that the women in serodiscordant couples were more likely to have undetectable or low plasma viral load (<1000 viral copies/mL) compared with women who were sex workers at baseline and at follow-up in the absence of antiretroviral therapy.

However, these findings are confounded by unmeasured variables, such as a likely difference in the distribution of sexually transmitted infections including between the 2 cohorts. In addition, unreported antiretroviral use by women with HIV in serodiscordant couples at study enrollment may have resulted in an overestimate of naturally occurring viral control.

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The study authors concluded that, “The results from this study highlight serodiscordant couples as a potentially important population for investigations of why some individuals naturally suppress virus, as well as potential identification of additional biological factors associated with lower risk of HIV transmission and acquisition.”1

References

1. Peebles K, McClelland RS, Overbaugh J, et al. Higher prevalence of viral control in HIV-1-infected women in serodiscordant  relationships. PLoS ONE. 2018;13(12): e0208401.

2. Hughes JP, Baeten JM, Lingappa JR, et al. Determinants of per-coital-act HIV-1 infectivity among African HIV-1-serodiscordant couples. J Infect Dis. 2012;205(3):358−365.

3. Baeten JM, Donnell D, Kapiga SH, et al. Male circumcision and risk of male-to-female HIV-1 transmission: a multinational prospective study in African HIV-1-serodiscordant couples. Aids. 2010;24(5):737−744.

4. Pinkerton SD. Probability of HIV transmission during acute infection in Rakai, Uganda. AIDS Behav. 2008;12(5):677−684.

5. Celum C, Wald A, Lingappa JR, et al. Acyclovir and transmission of HIV-1 from persons infected with HIV-1 and HSV-2. N Engl J Med. 2010;362(5):427−439.

6. Baeten JM, Donnell D, Ndase P, et al. Antiretroviral prophylaxis for HIV prevention in heterosexual men and women. N Engl J Med. 2012;367(5):399−410.

7. Gray RH, Wawer MJ, Brookmeyer R, et al. Probability of HIV-1 transmission per coital act in monogamous, heterosexual, HIV-1-discordant couples in Rakai, Uganda. Lancet. 2001;357(9263):1149−1153.

8. Wawer MJ, Gray RH, Sewankambo NK, et al. Rates of HIV-1 transmission per coital act, by stage of HIV-1 infection, in Rakai, Uganda. J Infect Dis. 2005;191(9):1403−1409.