British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada; Division of Infectious Diseases, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada.
Lancet HIV. 2024 Jul;11(7):e461-e469. doi: 10.1016/S2352-3018(24)00094-8. Epub 2024 Jun 4.
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) in British Columbia, Canada.
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 R. We calculated the modified effective reproduction number (R) using two thresholds of viral suppression and compared these values with R.
We found a 95% decline in HIV/AIDS-related mortality and a 91% decrease in HIV incidence over the study period. The R progressively declined from 1996 to 2022; however, from 1996 to 2017, R 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 R and R (<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.
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 R at a programmatic level to identify opportunities for the optimisation of treatment-as-prevention and PrEP programmes.
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.
治疗即预防和暴露前预防（PrEP）是控制艾滋病毒/艾滋病的关键策略。我们旨在描述在加拿大不列颠哥伦比亚省，抗逆转录病毒治疗（ART）、随后的治疗即预防以及 PrEP 的加入对艾滋病毒有效繁殖数（R）的纵向影响。
本人群水平的方案评估使用了不列颠哥伦比亚省艾滋病卓越中心（温哥华，不列颠哥伦比亚省，加拿大）的药物治疗计划的数据。我们还使用了加拿大公共卫生署的艾滋病毒发病率和流行率估计数、不列颠哥伦比亚省疾病控制中心每年新诊断的艾滋病毒病例数的数据以及不列颠哥伦比亚省生命统计署的死亡率数据。数据的获取时间取决于数据库来源，为 1985 年至 2022 年。结果是每年的艾滋病毒流行率、艾滋病毒发病率、新诊断的艾滋病毒病例数、接受抗逆转录病毒治疗的艾滋病毒感染者人数、艾滋病毒/艾滋病相关和全因死亡率、艾滋病毒发病率与全因死亡率的比值以及 R。我们使用两种病毒抑制阈值计算了修正后的有效繁殖数（R），并将这些值与 R 进行了比较。
在研究期间，艾滋病毒/艾滋病相关死亡率下降了 95%，艾滋病毒发病率下降了 91%。从 1996 年到 2022 年，R 逐渐下降；然而，从 1996 年到 2017 年，当为携带未被抑制病毒血症的艾滋病毒感染者计算 R 时，R 仍保持稳定（>1），这表明治疗即预防通过减少有潜在传播病毒能力的个体数量来降低艾滋病毒发病率。从 2018 年到 2022 年，无论我们考虑所有艾滋病毒感染者还是仅考虑那些病毒学未被抑制的感染者，观察到估计的 R 和 R（<1）下降。这一发现表明，PrEP 通过减少社区中易感染个体的数量来降低艾滋病毒发病率，而与病毒抑制无关。
我们的结果表明，普遍的治疗即预防和有针对性的 PrEP 在降低艾滋病毒发病率方面具有协同作用。这些发现支持在方案层面纳入对 R 的纵向监测，以确定优化治疗即预防和 PrEP 方案的机会。
不列颠哥伦比亚省卫生部、加拿大卫生部、加拿大公共卫生署、温哥华沿海卫生局、温哥华综合医院基金会、基因组不列颠哥伦比亚省和加拿大卫生研究院。
