Improvements in the HIV care continuum needed to meaningfully reduce HIV incidence among men who have sex with men in Baltimore, US: a modelling study for HPTN 078

Abstract

Introduction HIV prevalence is high among men who have sex with men (MSM) in Baltimore, Maryland, United States, and the levels of viral suppression among HIV‐positive MSM are relatively low. The HIV Prevention Trials Network 078 trial seeks to increase the levels of viral suppression among US MSM by increasing the rates of diagnosis and linkage to care and treatment. We estimated the increases in viral suppression needed to reach different HIV incidence reduction targets, and the impact of meeting diagnosis and treatment targets. Methods We used a mathematical model of HIV transmission among MSM from Baltimore, US, parameterised with behavioural data and fitted to HIV prevalence and care continuum data for Baltimore wherever possible, to project increases in viral suppression needed to reduce the HIV incidence rate among Baltimore MSM by 10, 20, 30 or 50% after 2, 5 and 10 years. We also projected HIV incidence reductions achieved if US national targets – 90% of people living with HIV (PLHIV) know their HIV serostatus, 90% of those diagnosed are retained in HIV medical care and 80% of those diagnosed are virally suppressed – or UNAIDS 90‐90‐90 targets (90% of PLHIV know their status, 90% of those diagnosed receive antiretroviral therapy (ART), 90% of those receiving ART are virally suppressed) are each met by 2020. Results To reduce the HIV incidence rate by 20% and 50% after five years (compared with the base‐case at the same time point), the proportion of all HIV‐positive MSM who are virally suppressed must increase above 2015 levels by a median 13 percentage points (95% uncertainty interval 9 to 16 percentage points) from median 49% to 60%, and 27 percentage points (22 to 35) from 49% to 75% respectively. Meeting all three US or 90‐90‐90 UNAIDS targets results in a 48% (31% to 63%) and 51% (38% to 65%) HIV incidence rate reduction in 2020 respectively. Conclusions Substantial improvements in levels of viral suppression will be needed to achieve significant incidence reductions among MSM in Baltimore, and to meet 2020 US and UNAIDS targets. Future modelling studies should additionally consider the impact of pre‐exposure prophylaxis for MSM.

Understanding the HIV Epidemic Among MSM in Baltimore: A Modeling Study Estimating the Impact of Past HIV Interventions and Who Acquired and Contributed to Infections

“…4,5 The high HIV infection rate among US MSM has been associated with low condom use, 6 high numbers of non-steady partnerships, 7,8 and low levels of viral suppression because levels of both HIV diagnosis and retention in care among US MSM are suboptimal. [9][10][11] Baltimore, Maryland, is a major US city whose population is primarily non-Hispanic black or African American (63%) (hereafter referred to as black) and non-Hispanic white (hereafter referred to as white) (28%). 12 HIV prevalence among MSM in Baltimore, MD, estimated at 43% in 2011 and 37% in 2017, is one of the highest in the United States.…”

Assessing the use of surveillance data to estimate the impact of prevention interventions on HIV incidence in cluster-randomized controlled trials

“…We used a previously published HIV transmission and treatment model for US MSM ( Mitchell et al, 2019 ), and included PrEP. Briefly, it is a deterministic compartmental model of sexual HIV transmission, which divides the population by age, race, HIV infection stage and HIV care continuum engagement.…”

“…The model was previously fitted to Baltimore MSM data in a Bayesian framework involving varying 117 parameters and giving 169 parameter combinations (model fits) which reproduce well HIV prevalence trends, demography and HIV care continuum outcomes ( Mitchell et al, 2019 ). We retained these 169 parameter combinations, and for each combination additionally selected PrEP parameter values giving PrEP coverage consistent with Baltimore MSM data ( Hoots et al, 2016 ; Centers for Disease Control and Prevention, 2019 ) (details in supplementary material ).…”

“…We used a calibrated mathematical model of HIV transmission and treatment among men who have sex with men (MSM) in the US ( Mitchell et al, 2019 ) to inform the design of a proposed C-RCT of combination HIV prevention in this population, including provision of and support for increased HIV testing, immediate ART for HIV-infected individuals, and PrEP for at-risk uninfected individuals. During proposal development, it was suggested that county-level surveillance data on new HIV diagnoses be used to estimate cumulative HIV incidence reductions over a two-year period.…”

Modeling an Integrated HIV Prevention and Care Continuum to Achieve the Ending the HIV Epidemic Goals

“…9 Prior models evaluating the HIV care continuum for people with HIV in the United States (U.S.) have suggested that major improvements to HIV screening, care linkage, and care retention would be needed to achieve substantial reductions in HIV transmission. [10][11][12][13] Models focused on HIV-uninfected populations have projected the impact of PrEP given low coverage and poor persistence. [14][15][16] Despite this strong modeling research base, the potential for synergy between the HIV care and prevention continua has not been sufficiently evaluated.…”