1. Longitudinal evolution of the HIV effective reproduction number following sequential expansion of treatment as prevention and pre-exposure prophylaxis in British Columbia, Canada: a population-level programme evaluation.
- Author
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Lima VD, Zhu J, Barrios R, Toy J, Joy JB, Williams BG, Granich R, Wu Z, Wong J, and Montaner JSG
- Subjects
- Humans, British Columbia epidemiology, Incidence, Male, Female, Prevalence, Longitudinal Studies, Adult, Middle Aged, Basic Reproduction Number, Pre-Exposure Prophylaxis, HIV Infections drug therapy, HIV Infections prevention & control, HIV Infections epidemiology, Program Evaluation, Anti-HIV Agents therapeutic use, Anti-HIV Agents administration & dosage
- Abstract
Background: Treatment as prevention and pre-exposure prophylaxis (PrEP) are key strategies in the control of HIV/AIDS. We aimed to characterise the longitudinal effects of antiretroviral therapy (ART), followed by treatment as prevention and the addition of PrEP, on the HIV effective reproduction number (R
e ) in British Columbia, Canada., Methods: This population-level programme evaluation used data from the Drug Treatment Program of the British Columbia Centre for Excellence in HIV/AIDS (Vancouver, British Columbia, Canada). We also used estimates of HIV incidence and prevalence from the Public Health Agency of Canada, data on the number of new HIV diagnoses per year from the British Columbia Centre for Disease Control, and mortality data from the British Columbia Vital Statistics Agency. Data were obtained from 1985 until 2022, depending on the database source. Outcomes were the annual HIV prevalence, HIV incidence, number of new HIV diagnoses, number of people living with HIV on ART, HIV/AIDS-related and all-cause mortality rates, the HIV incidence-to-all-cause-mortality ratio, and Re . We calculated the modified effective reproduction number (Rme ) using two thresholds of viral suppression and compared these values with Re ., Findings: We found a 95% decline in HIV/AIDS-related mortality and a 91% decrease in HIV incidence over the study period. The Re progressively declined from 1996 to 2022; however, from 1996 to 2017, Rme remained stable (>1) when calculated for people living with HIV with unsuppressed viraemia, suggesting that treatment as prevention reduces HIV incidence by decreasing the pool of individuals who are potentially able to transmit the virus. From 2018 to 2022, a decline in the estimated Re and Rme (<1) was observed regardless of whether we considered all people living with HIV or only those who were virologically unsuppressed. This finding suggests that PrEP decreases HIV incidence by reducing the number of susceptible individuals in the community, independently of viral suppression., Interpretation: Our results show the synergy between generalised treatment as prevention and targeted PrEP in terms of decreasing HIV incidence. These findings support the incorporation of longitudinal monitoring of Re at a programmatic level to identify opportunities for the optimisation of treatment-as-prevention and PrEP programmes., Funding: British Columbia Ministry of Health, Health Canada, Public Health Agency of Canada, Vancouver Coastal Health, Vancouver General Hospital Foundation, Genome British Columbia, and the Canadian Institutes of Health Research., Competing Interests: Declaration of interests JSGM received institutional grants from Gilead Sciences, Merck, and ViiV Healthcare. VDL received honoraria to present at the 2023 Conference on Retroviruses and Opportunistic Infections ViiV Healthcare Ambassador Program. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)- Published
- 2024
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