Human papillomavirus seropositivity and subsequent risk of HIV acquisition in rural South African women.

OBJECTIVE: This study aimed to provide a population-based estimate of human papillomavirus (HPV) seropositivity for women in a rural African context and to evaluate the impact of HPV serostatus on subsequent acquisition of HIV outside a clinical setting. DESIGN: A random sample of women participating in a longitudinal, population-based HIV survey combined with a case-control study. METHODS: Blood samples of women participating in a single round of population-based HIV surveillance (N = 1049) in a rural South African population were used to measure vaccine-preventable HPV seropositivity (types 6, 11, 16, and 18) in the general population in 2010. Using results from the repeat HIV surveys, a case-control analysis was then performed comparing HPV sero-status in samples taken from HIV sero-converting women (prior to infection with HIV) against samples from HIV-uninfected, sexually-active controls matched 1:1 according to 5-year age band (377:377). Unconditional multivariable logistic regression with multiple imputations was used to control for sociodemographic and behavioral variables associated with HIV acquisition. RESULTS: Human papillomavirus seropositivity in the population-based sample of women was 20.8% (95% confidence interval [CI], 18.3-23.4), and HIV prevalence was 27.6% (95% CI, 24.9-30.4). In the case-control analysis, allowing for variables known to be associated with HIV incidence, HPV seropositivity was associated with nearly 2.5 times the odds of subsequent acquisition of HIV (adjusted odds ratio, 2.33 [95% CI, 1.61-3.39]; P < 0.001). CONCLUSIONS: These results suggest that HPV vaccination before or soon after sexual debut could lower HIV infection risk. Randomized trials that quantify the impact of HPV vaccination in girls on the risk of acquiring HIV are urgently required.

Does antiretroviral therapy change partnership dynamics and HIV risk behaviours among HIV-infected adults.

OBJECTIVE: We explore the impact of antiretroviral therapy (ART) on partnership acquisition and dissolution rates and changes in sexual behaviours among HIV-infected adults. DESIGN: Using detailed longitudinal data from a prospective cohort of HIV-infected adults with CD4 cell count below 200 cells/µl (ART-eligible) or CD4 cell count above 500 cells/µl (pre-ART) conducted in rural KwaZulu-Natal, South Africa, from 2009 to 2012. METHODS: Partnership acquisition and dissolution are explored through survival analysis methods, whereas generalized linear models were fitted for the sexual behaviour outcomes with interaction terms to allow the association with ART to vary over time. Throughout, the primary comparison of interest for each outcome is differences between the two ART groups. RESULTS: ART is not associated with partner acquisition or relationship dissolution. During follow-up, the two ART groups do not differ in the odds of being sexually active nor the number of sex acts, whereas the odds of unprotected sex are significantly lower for partnerships of ART-eligible participants (adjusted odds ratio 0.26, 95% confidence interval 0.15, 0.43). Relationship-level characteristics including cohabitation status and wanting more children with that partner are associated with higher odds and increased frequency of sexual activity, and increased odds of unprotected sex, whereas living with partner, higher relationship quality and longer relationship duration are associated with lower risk of partnership dissolution. CONCLUSION: Being on ART was not associated with increased sexual risk behaviours, a reassuring finding given the WHO recommends ART initiation upon HIV diagnosis. The importance of relationship-level characteristics provides evidence that HIV care services should offer routine support for HIV disclosure and sexual risk reduction, and promotion of couples-testing and positive couple relationships.

High coverage of ART associated with decline in risk of HIV acquisition in rural KwaZulu-Natal, South Africa.

The landmark HIV Prevention Trials Network (HPTN) 052 trial in HIV-discordant couples demonstrated unequivocally that treatment with antiretroviral therapy (ART) substantially lowers the probability of HIV transmission to the HIV-uninfected partner. However, it has been vigorously debated whether substantial population-level reductions in the rate of new HIV infections could be achieved in "real-world" sub-Saharan African settings where stable, cohabiting couples are often not the norm and where considerable operational challenges exist to the successful and sustainable delivery of treatment and care to large numbers of patients. We used data from one of Africa's largest population-based prospective cohort studies (in rural KwaZulu-Natal, South Africa) to follow up a total of 16,667 individuals who were HIV-uninfected at baseline, observing individual HIV seroconversions over the period 2004 to 2011. Holding other key HIV risk factors constant, individual HIV acquisition risk declined significantly with increasing ART coverage in the surrounding local community. For example, an HIV-uninfected individual living in a community with high ART coverage (30 to 40% of all HIV-infected individuals on ART) was 38% less likely to acquire HIV than someone living in a community where ART coverage was low (<10% of all HIV-infected individuals on ART).

Modelling HIV incidence and survival from age-specific seroprevalence after antiretroviral treatment scale-up in rural South Africa.

OBJECTIVE: Our study uses sex-specific and age-specific HIV prevalence data from an ongoing population-based demographic and HIV survey to infer HIV incidence and survival in rural KwaZulu-Natal between 2003 and 2011, a period when antiretroviral treatment (ART) was rolled out on a large scale. DESIGN: Catalytic mathematical model for estimating HIV incidence and differential survival in HIV-infected persons on multiple rounds of HIV seroprevalence. METHODS: We evaluate trends of HIV incidence and survival by estimating parameters separately for women and men aged 15-49 years during three calendar periods (2003-2005, 2006-2008, 2009-2011) reflecting increasing ART coverage. We compare model-based estimates of HIV incidence with observed cohort-based estimates from the longitudinal HIV surveillance. RESULTS: Median survival after HIV infection increased significantly between 2003-2005 and 2009-2011 from 10.0 [95% confidence interval (CI) 8.8-11.2] to 14.2 (95% CI 12.6-15.8) years in women (P < 0.001) and from 10.0 (95% CI 9.2-10.8) to 14.0 (95% CI 10.6-17.4) years in men (P = 0.02). Our model suggests no statistically significant reduction of HIV incidence in the age-group 15-49 years in 2009-2011 compared with 2003-2005. Age-specific and sex-specific model-based HIV incidence estimates were in good agreement with observed cohort-based estimates from the ongoing HIV surveillance. CONCLUSION: Our catalytic modelling approach using cross-sectional age-specific HIV prevalence data could be useful to monitor trends of HIV incidence and survival in other African settings with a high ART coverage.

Dramatic increase in HIV prevalence after scale-up of antiretroviral treatment.

OBJECTIVES: To investigate HIV prevalence trends in a rural South African community after the scale-up of antiretroviral treatment (ART) in 2004. METHODS: We estimated adult HIV prevalence (ages 15-49 years) using data from a large, longitudinal, population-based HIV surveillance in rural KwaZulu-Natal, South Africa, over the period from 2004 (the year when the public-sector ART scale-up started) to 2011. We control for selection effects due to surveillance nonparticipation using multiple imputation. We further linked the surveillance data to patient records from the local HIV treatment program to estimate ART coverage. RESULTS: ART coverage of all HIV-infected people in this community increased from 0% in 2004 to 31% in 2011. Over the same observation period adult HIV prevalence increased steadily from 21 to 29%. The change in overall HIV prevalence is nearly completely explained by an increase of HIV-infected people receiving ART, and it is largely driven by increases in HIV prevalence in women and men older than 24 years. CONCLUSION: The observed dramatic increase in adult HIV prevalence can most likely be explained by increased survival of HIV-infected people due to ART. Future studies should decompose HIV prevalence trends into HIV incidence and HIV-specific mortality changes to further improve the causal attribution of prevalence increases to treatment success rather than prevention failure.