HIV reduction efforts should target risky behaviors

Expanding HIV screening and treatment would help reduce new HIV infections, but prevention efforts should also target risky behaviors to be most effective, a new study indicates.

Approximately 56,000 people become infected with HIV each year in the U.S., and recent clinical guidelines recommend expanding HIV screening to all patients 13 and older regardless of risk factors. Researchers developed a mathematical model and performed a cost-effectiveness analysis to evaluate the effect of expanded screening, antiretroviral therapy (ART) and behavioral counseling on the U.S. HIV epidemic. The goal of the study was to determine whether expanding screening, treatment or both could significantly decrease HIV infections in the U.S., and whether more infections could be prevented by allocating resources to screening or to treatment. Effects of reductions in risky behavior were also evaluated. The study results appear in the Dec. 21 Annals of Internal Medicine.

The authors' model projected that about 1.23 million new HIV infections would occur in 20 years, 74% in persons at high risk. In the base-case analysis, one-time HIV screening in low-risk persons and annual screening of high-risk persons prevented 6.7% of these infections at a cost per quality-adjusted life-year (QALY) gained of $22,382 when a 20% reduction in sexual activity after screening was assumed. When ART use was expanded to 75% of eligible patients, 10.3% of infections were prevented at a cost of $20,300 QALY gained. A strategy that combined both expanded screening and treatment prevented 17.3% of infections at a cost of $21,580 per QALY gained. The sensitivity analysis, meanwhile, found that expanded screening could prevent 3.7% of infections if sexual activity wasn't reduced, that earlier initiation of ART could prevent 20% to 28% of infections, and that efforts to halve high-risk behavior could reduce new infections by 65%.

The study used a simplified model of disease progression and treatment, did not consider variations in race or ethnicity, and excluded acute HIV screening. Nevertheless, the authors wrote, their results indicate that a multimodal program could markedly affect HIV incidence in the U.S. over the next two decades, with expanded screening and treatment programs leading to a potential 24% reduction. They pointed out that the cost-effectiveness of one-time HIV screening in low-risk persons and annual screening in high-risk persons is comparable to that of screening for type 2 diabetes and mammography screening for breast cancer. "If these [screening and treatment] programs are accompanied by additional interventions that halve risky sexual and needle-sharing behavior, the epidemic could be reduced by 65%, suggesting the need for a comprehensive portfolio of HIV prevention, screening, and treatment," they concluded.