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Universal access to preventive drugs could reduce HIV incidence in sub-Saharan Africa

Universal HIV testing with linkage to treatment and prevention may be a promising approach to accelerate reductions in new infections in generalized epidemic settings, according to a study by Catherine Koss of the University of California-San Francisco, and colleagues.

Despite major gains in HIV testing and treatment, in 2019 there were 1.7m new HIV infections, of which nearly 60% occurred in sub-Saharan Africa. Daily oral pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate/emtricitabine is highly effective for HIV prevention and could substantially reduce new HIV infections if offered alongside access to HIV testing and treatment. But little is known about the incidence of new HIV infections among PrEP users in settings with generalized HIV epidemics, particularly outside of selected risk groups.

To address this knowledge gap, Koss and colleagues conducted community-based HIV testing and offered universal access to PrEP in 16 communities in the Sustainable East Africa Research in Community Health (SEARCH) study in rural Kenya and Uganda. They offered rapid or same-day PrEP initiation and flexible service delivery with follow-up visits at facilities or community-based sites over a period of 144 weeks. According to the authors, this study is the first in sub-Saharan Africa to assess HIV incidence after offering PrEP at a population level.

Among 74,541 individuals who tested negative for HIV, 21% were assessed to be at elevated HIV risk, and 5,447 (35%) of those individuals initiated PrEP, with 79% participating in follow-up visits. Over 7,150 person-years of follow-up, HIV incidence was 0.35 per 100 person-years (95% CI 0.22-0.49) among PrEP initiators. Among matched historical controls in 8 of the communities, HIV incidence was 0.92 per 100 person-years (95% CI 0.49-1.41) over the year prior to PrEP availability. Compared to matched historical controls, HIV incidence was 74% lower overall in PrEP initiators in 8 of the communities (adjusted incidence rate ratio [aIRR] 0.26, 95% CI 0.09-0.75; p=0.013), and 76% lower among women (aIRR 0.24, 95% CI 0.07-0.79; p=0.019), but not significantly lower in men. Data on HIV incidence among historical controls were not available for the remaining 8 communities.

Because rates of new HIV infections are higher in women than in men, the results suggest that PrEP may help to close the gender gap in new infections. According to the authors, universal access to HIV testing, treatment, and prevention, including rapid provision of PrEP with flexible service delivery, could reduce HIV incidence in generalized epidemic settings.

Dr Moses Kamya states “We know that PrEP is highly effective – and now we need systems that make it easier to start and continue taking it. This study showed that providing broad access to PrEP in community-based settings significantly reduced HIV incidence.”

Koss adds “We found that universal HIV testing with easy access to PrEP was associated with lower rates of HIV, particularly among women.”

 

Study details
HIV incidence after pre-exposure prophylaxis initiation among women and men at elevated HIV risk: A population-based study in rural Kenya and Uganda

Catherine A Koss, Diane V Havlir, James Ayieko, Dalsone Kwarisiima, Jane Kabami, Gabriel Chamie, Mucunguzi Atukunda, Yusuf Mwinike, Florence Mwangwa, Asiphas Owaraganise, James Peng, Winter Olilo, Katherine Snyman, Benard Awuonda, Tamara D Clark, Douglas Black, Joshua Nugent, Lillian B Brown, Carina Marquez, Hideaki Okochi, Kevin Zhang, Carol S Camlin, Vivek Jain, Monica Gandhi, Craig R Cohen, Elizabeth A Bukusi, Edwin D Charlebois, Maya L Petersen, Moses R Kamya, Laura B Balzer

Published in PLOS Medicine on 9 February 2021

Abstract
Background
Oral pre-exposure prophylaxis (PrEP) is highly effective for HIV prevention, but data are limited on HIV incidence among PrEP users in generalized epidemic settings, particularly outside of selected risk groups. We performed a population-based PrEP study in rural Kenya and Uganda and sought to evaluate both changes in HIV incidence and clinical and virologic outcomes following seroconversion on PrEP.
Methods and findings
During population-level HIV testing of individuals ≥15 years in 16 communities in the Sustainable East Africa Research in Community Health (SEARCH) study (NCT01864603), we offered universal access to PrEP with enhanced counseling for persons at elevated HIV risk (based on serodifferent partnership, machine learning–based risk score, or self-identified HIV risk). We offered rapid or same-day PrEP initiation and flexible service delivery with follow-up visits at facilities or community-based sites at 4, 12, and every 12 weeks up to week 144. Among participants with incident HIV infection after PrEP initiation, we offered same-day antiretroviral therapy (ART) initiation and analyzed HIV RNA, tenofovir hair concentrations, drug resistance, and viral suppression (<1,000 c/ml based on available assays) after ART start. Using Poisson regression with cluster-robust standard errors, we compared HIV incidence among PrEP initiators to incidence among propensity score–matched recent historical controls (from the year before PrEP availability) in 8 of the 16 communities, adjusted for risk group. Among 74,541 individuals who tested negative for HIV, 15,632/74,541 (21%) were assessed to be at elevated HIV risk; 5,447/15,632 (35%) initiated PrEP (49% female; 29% 15–24 years; 19% in serodifferent partnerships), of whom 79% engaged in ≥1 follow-up visit and 61% self-reported PrEP adherence at ≥1 visit. Over 7,150 person-years of follow-up, HIV incidence was 0.35 per 100 person-years (95% confidence interval [CI] 0.22–0.49) among PrEP initiators. Among matched controls, HIV incidence was 0.92 per 100 person-years (95% CI 0.49–1.41), corresponding to 74% lower incidence among PrEP initiators compared to matched controls (adjusted incidence rate ratio [aIRR] 0.26, 95% CI 0.09–0.75; p = 0.013). Among women, HIV incidence was 76% lower among PrEP initiators versus matched controls (aIRR 0.24, 95% CI 0.07–0.79; p = 0.019); among men, HIV incidence was 40% lower, but not significantly so (aIRR 0.60, 95% CI 0.12–3.05; p = 0.54). Of 25 participants with incident HIV infection (68% women), 7/25 (28%) reported taking PrEP ≤30 days before HIV diagnosis, and 24/25 (96%) started ART. Of those with repeat HIV RNA after ART start, 18/19 (95%) had <1,000 c/ml. One participant with viral non-suppression was found to have transmitted viral resistance, as well as emtricitabine resistance possibly related to PrEP use. Limitations include the lack of contemporaneous controls to assess HIV incidence without PrEP and that plasma samples were not archived to assess for baseline acute infection.
Conclusions
Population-level offer of PrEP with rapid start and flexible service delivery was associated with 74% lower HIV incidence among PrEP initiators compared to matched recent controls prior to PrEP availability. HIV infections were significantly lower among women who started PrEP. Universal HIV testing with linkage to treatment and prevention, including PrEP, is a promising approach to accelerate reductions in new infections in generalized epidemic settings.

 

[link url="https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003492"]PLOS Medicine study (Open access)[/link]

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