Averting HIV Infections in New York City: A Modeling Approach Estimating the Future Impact of Additional Behavioral and Biomedical HIV Prevention Strategies

Abstract

BackgroundNew York City (NYC) remains an epicenter of the HIV epidemic in the United States. Given the variety of evidence-based HIV prevention strategies available and the significant resources required to implement each of them, comparative studies are needed to identify how to maximize the number of HIV cases prevented most economically.MethodsA new model of HIV disease transmission was developed integrating information from a previously validated micro-simulation HIV disease progression model. Specification and parameterization of the model and its inputs, including the intervention portfolio, intervention effects and costs were conducted through a collaborative process between the academic modeling team and the NYC Department of Health and Mental Hygiene. The model projects the impact of different prevention strategies, or portfolios of prevention strategies, on the HIV epidemic in NYC.ResultsTen unique interventions were able to provide a prevention benefit at an annual program cost of less than $360,000, the threshold for consideration as a cost-saving intervention (because of offsets by future HIV treatment costs averted). An optimized portfolio of these specific interventions could result in up to a 34% reduction in new HIV infections over the next 20 years. The cost-per-infection averted of the portfolio was estimated to be $106,378; the total cost was in excess of $2 billion (over the 20 year period, or approximately $100 million per year, on average). The cost-savings of prevented infections was estimated at more than $5 billion (or approximately $250 million per year, on average).ConclusionsOptimal implementation of a portfolio of evidence-based interventions can have a substantial, favorable impact on the ongoing HIV epidemic in NYC and provide future cost-saving despite significant initial costs.

Evaluating the impact of prioritization of antiretroviral pre-exposure prophylaxis in New York

“…We have shown that 24% of new HIV infections could be averted with modest assumptions about PrEP uptake and effectiveness when utilized within the larger community at-risk of HIV acquisition in NYC. We have previously reported on less expensive combination prevention strategies that are able to avert similar proportions of HIV infections over a similar time frame [17]. Prioritizing PrEP to high-risk populations would be reasonable to produce health gains in an economically feasible and efficient manner [30].…”

“…This mathematical model integrates equilibrium results from a Monte Carlo simulation of HIV progression with a deterministic compartmental model of HIV transmission [17]. The model incorporates both sexual transmission and transmission through needle-sharing during injection drug use.…”

“…A cost-per-infection averted ratio between $0.36 million – $1 million was considered as likely cost-saving because a more recent evaluation of the lifetime costs of care for individuals with HIV/AIDS suggests higher costs [19]. More complete details of model specification, initial population structure and parameterization have been published elsewhere [17]. …”

“…We used a previously developed epidemic model of both sexual and injection drug use transmission to simulate PrEP use among various populations [17]. We sought to examine and compare both the effectiveness and value of PrEP implementation among different communities at risk of HIV acquisition (prioritization strategies) including both those addressed in previous models (e.g.…”

A call to action for concentrated HIV epidemics

“…Research by Vickerman and colleagues [46] indicates that the hepatitis C coinfection prevalence among HIV positive PWID may be an important marker for understanding the proportion of HIV infections due to injection versus sexual transmission among PWID. Bioly and Shubber note that recent models indicate that PrEP and treatment-as-prevention may be cost-effective but ideally targeted towards higher risk individuals [47–49], and that needle and syringe exchange programs, opioid-substitution therapy, and condom use are highly cost-effective [50–54] and, in some settings, may be sufficient to substantially reduce long-term HIV prevalence [55;56]. …”