A Mathematical Model of Comprehensive Test-and-Treat Services and HIV Incidence among Men Who Have Sex with Men in the United States

<div><h3>Background</h3><p>Early diagnosis and treatment of HIV infection and suppression of viral load are potentially powerful interventions for reducing HIV incidence. A test-and-treat strategy may have long-term effects on the epidemic among urban men who have sex with men (MSM) in the United States and may achieve the 5-year goals of the 2010 National AIDS Strategy that include: 1) lowering to 25% the annual number of new infections, 2) reducing by 30% the HIV transmission rate, 3) increasing to 90% the proportion of persons living with HIV infection who know their HIV status, 4) increasing to 85% the proportion of newly diagnosed patients linked to clinical care, and 5) increasing by 20% the proportion of HIV-infected MSM with an undetectable HIV RNA viral load.</p> <h3>Methods and Findings</h3><p>We constructed a dynamic compartmental model among MSM in an urban population (based on New York City) that projects new HIV infections over time. We compared the cumulative number of HIV infections in 20 years, assuming current annual testing rate and treatment practices, with new infections after improvements in the annual HIV testing rate, notification of test results, linkage to care, initiation of antiretroviral therapy (ART) and viral load suppression. We also assessed whether five of the national HIV prevention goals could be met by the year 2015. Over a 20-year period, improvements in test-and-treat practice decreased the cumulative number of new infections by a predicted 39.3% to 69.1% in the urban population based on New York City. Institution of intermediate improvements in services would be predicted to meet at least four of the five goals of the National HIV/AIDS Strategy by the 2015 target.</p> <h3>Conclusions</h3><p>Improving the five components of a test-and-treat strategy could substantially reduce HIV incidence among urban MSM, and meet most of the five goals of the National HIV/AIDS Strategy.</p> </div

Values for input parameters for the model and references.

<p>*Calculated in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0029098#pone.0029098.s001" target="_blank">Appendix S1</a>.</p><p>**Calculated from New York City Community Health Survey.</p

Prevalence of HIV infections over 20 years for MSM in New York City, percent.

<p>Prevalence of HIV infections over 20 years for MSM in New York City, percent.</p

Annual number of new HIV infections over 20 years for MSM in New York City.

<p>Annual number of new HIV infections over 20 years for MSM in New York City.</p

Reduction in new infections from HIV annual testing, notification, linkage to care, treatment, and viral load suppression.

<p>Reduction in new infections from HIV annual testing, notification, linkage to care, treatment, and viral load suppression.</p

Sensitivity analyses for MSM in New York City.

<p>*The sensitivity analyses' results are compared to the current practice in which HIV-infected MSM aware of their infection use condoms for 75% of sex acts, compared with condom use for 50% of sex acts among persons who are HIV-infected but unaware of it. In addition, among HIV-infected MSM who achieve viral load suppression receiving ART in the current practice analysis, per-contact transmission risk is reduced 90% compared to HIV-infected MSM whose viral load is not suppressed.</p