Potential Impact on HIV Incidence Ofincreasingviral Suppression Among HIV-Positive MSM

Potential Impact on HIV Incidence ofIncreasingViral Suppression among HIV-positive MSM in Baltimore: Mathematical Modelling for HPTN 078.

Authors: Kate M Mitchell1, Brooke Hoots2, Dobromir Dimitrov3, Jason Farley4, Marcy Gelman5, Danielle German4, Colin Flynn6, Robert H Remien7, Chris Beyrer4,Gabriela Paz-Bailey2, Marie-Claude Boily1

1Imperial College London, HPTN Modelling Centre, London, United Kingdom

2Centers for Disease Control and Prevention, Atlanta, GA, United States

3Fred Hutchinson Cancer Research Center, Seattle, WA, United States

4Johns Hopkins University, Baltimore, MD, United States

5Fenway Institute, Boston, MA, United States

6Maryland Department of Health and Mental Hygiene, Baltimore, MD, United States

7HIV Center for Clinical and Behavioral Studies, NY State Psychiatric Institute and Columbia University, New York, NY, United States

Character count: 2,000 (limit 2000)

Background

In 2011, 41% of men who have sex with men(MSM) in Baltimore were estimated to be HIV-positive, of whom an estimated19-24%werevirally suppressed(~31% in 2013). HPTN 078 aims to increase MSMviral suppression(VS) levelsover 2 years. We assessedthe VS increase neededto meet infection reduction targets(IRTs) of averting 20 or 50% of new MSM HIV infectionsover 5/10 years(by 2021/2026)taking into account uncertainties in the age/race distributionand VS level of MSM.

Methods

A race/age-stratified MSM HIV transmission and treatment model was parameterised withBaltimore behavioral data from 2004-2011 National HIV Behavioral Surveillance(NHBS). The model wasfitted assumingthatNHBS(Scenario A) or census(Scenario B) age/race data were representative of MSM, withVSvarying between different local and national estimates. We used a Bayesian framework to identify multiple parameter sets reproducingage/race-specific NHBS HIV prevalence, and used theseto estimatethe increase (median [IQR]) in VS(through increased testing/linkage/treatment initiation and/or reduced dropout from care and treatment, starting in 2016) needed to meet IRTs.

Results

Preliminary results showsimilar VS increasesareneeded with Scenarios AB to meet IRTsfor MSM.Scenario A:51% (43-66%)relative increase in VS after 2 years is needed, from a median 32% (without intervention)to 47%, to reach an IRT of 20% over 5 yrs. Scenario B:54% (41-65%) relative VS increase is needed.Results were sensitive to initial VS: if <=30% or >30% of MSM were suppressed in 2016a relative 61% or 43%VS increase (up to 42% or 52% virally suppressed in 2018) was needed to reach a 20% IRT over 5 yrs, respectively. Smaller increases(~32% after 2 yrs) were needed to reach this IRT over 10 yrs. 50% IRTswere not always achievable even with >70% VS.

Conclusions

Large increases in VS are needed to achieve moderate reductionsin new HIV infections among Baltimore MSM, especially short-term. Results are robust forMSM demography assumptions