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Metrics and benchmarks for HIV transition

2019; Elsevier BV; Volume: 6; Issue: 3 Linguagem: Inglês

10.1016/s2352-3018(19)30050-5

2405-4704

Peter D. Ghys, Mead Over, Timothy B. Hallett, Mary Mahy, Peter Godfrey‐Faussett,

Adolescent Sexual and Reproductive Health

In their Viewpoint, Alison Galvani and colleagues1Galvani AP Pandey A Fitzpatrick MC Medlock J Gray GE Defining control of HIV epidemics.Lancet HIV. 2018; 5: e667-e670Summary Full Text Full Text PDF PubMed Scopus (34) Google Scholar draw attention to the discussion on metrics that could define “control of HIV epidemics”. We agree that the different metrics have their strengths and weaknesses and that it is important to consider carefully how such metrics for transition in the HIV epidemic should be interpreted.2Ghys PD Williams BG Over M Hallett TB Godfrey-Faussett P Epidemiological metrics and benchmarks for a transition in the HIV epidemic.PLoS Med. 2018; 15: e1002678Crossref PubMed Scopus (36) Google Scholar We were surprised that their analysis assumes future “status quo interventions”, given that “control of HIV epidemics” implies future progress in the response rather than “status quo interventions”. Of note, such assumptions are inconsistent with available data for recent years; for example, trends in HIV incidence and AIDS-related mortality in sub-Saharan Africa are downward, whereas Galvani and colleagues anticipate an upward trajectory. Also, whereas Galvani and colleagues expect that the population of young people will shortly start to increase, there has in fact been strong growth in that group throughout the past course of the HIV epidemic in sub-Saharan Africa, but in future years the proportion of young people 15–24 years old out of the 15–99 year old population is expected to decline from 34% in 2020 to 28% in 2050 (data retrieved Jan 17). Because definitions of control using the incidence-to-mortality ratio (IMR)2Ghys PD Williams BG Over M Hallett TB Godfrey-Faussett P Epidemiological metrics and benchmarks for a transition in the HIV epidemic.PLoS Med. 2018; 15: e1002678Crossref PubMed Scopus (36) Google Scholar specify mortality reduction as a precondition, we were also surprised that the authors have depicted scenarios for South Africa and sub-Saharan Africa in which mortality rises above incidence and characterised these scenarios as satisfying the IMR criterion for control. Some authors3Williams BG Granich R Ending AIDS: myth or reality?.Lancet. 2017; 390: 357Summary Full Text Full Text PDF PubMed Scopus (10) Google Scholar have proposed annual incidence of 1 in 1000 as a threshold and others, like the Viewpoint authors, choose 1 in 10 000. Importantly, despite what Galvani and colleagues imply, such a target would be arbitrary and would not conform to any important precedent set by WHO. Prof Tim Hallett reports a grant from the Bill and Melinda Gates Foundation in support of mathematical modelling. All other authors declare no competing interests. Defining control of HIV epidemicsAlthough the HIV pandemic remains a global crisis, much progress has been made in implementing programmes to treat and prevent HIV infection. To guide prioritisation of efforts, the metric by which a country can declare its HIV epidemic as controlled has become increasingly relevant. Herein, we evaluate the merits of the four control criteria proposed by UNAIDS: percentage reduction in incidence over time; ratio of incidence to mortality; ratio of incidence to prevalence; and annual incidence. Using a transmission model to generate projections of demography, incidence, and mortality, we highlight potential pitfalls associated with each of the first three criteria. Full-Text PDF Metrics and benchmarks for HIV transition – Authors' replyAlthough estimates provided by Peter Ghys and colleagues indicate a marginal decline in the proportion of 15–24 year olds by 2050, even with these estimates the number of people in this age range will double during the same period. Consequently, HIV incidence rates would need to be halved to ensure that the total number of new cases in that age group remains the same, which would be unlikely without sustained and amplified efforts. Full-Text PDF