Speaker
Description
Molecular epidemiology and evolutionary genetic methods can provide critical insights into public health program performance and quantitatively direct programmatic enhancements. The United Nations (UN) targets: 95-95-95 by 2025 Targets, aim to decrease AIDS deaths and HIV new infections by at least 90% by 2030, meeting the UN-defined “End of HIV/AIDS as a pandemic concern”. Herein, we develop and present a fifth epidemiological parameter that we propose be considered as part of the HIV/AIDS control targets. Specifically, we propose and evaluate a 5th 90: the rate of reduction in phylogenetic cluster-associated cases needed to supplement current. Furthermore, we present insights derived from 10 years of continuous phylogenetic monitoring. We inferred molecular phylogenies from 42,043 anonymized HIV partial pol sequences from 10,740 individuals living with HIV in B.C. Clusters of 5 or more individuals were inferred based on a phylogenetic distance of 0.02 substitutions/site. Rates of acquisition of new cluster members and birth of new clusters were quantified between 2010 and 2023 based on individuals' first sample collection dates. Overall, individuals were grouped into 309 transmission clusters primarily segregated by transmission risk factors. We observed a strong recent decline in the proportion of new HIV cases joining transmission clusters. Furthermore, we observed a strong year-over-year decline in the birth of new clusters. We present a new epidemiological parameter for consideration as an additional UN Target, the proportion of new HIV diagnoses associated with transmission clusters. Increases in this parameter indicate a rise in local transmission, conversely, decreases suggest public health programs are effectively suppressing local transmission and new diagnoses from imported cases. Our case study of this new parameter in BC provides evidence for strong declines in local transmission. Metrics derived longitudinally from clusters can provide key summary insights into epidemic dynamics.
