Published by the Students of Johns Hopkins since 1896
September 19, 2020

HIV screenings could prevent new infections

By JOAN YEA | November 19, 2015

Advancements in antiretroviral therapy (ART) in recent years have enabled human immunodeficiency virus (HIV) patients to benefit from fewer side effects as well as less stringent dosing schedules.

U.S. treatment protocols now recommend that ART, which is currently recognized as a powerful tool for stemming HIV transmission, be initiated at earlier stages in the treatment process. Patients can enjoy longer and healthier lives with the timely initiation of ART because of viral suppression and the improved function of their immune systems. Moreover the resulting reduced viral load helps reduce the risk of more HIV transmissions.

However efforts to prevent HIV transmission via widespread screening programs and early initiation of treatment are compromised by the lack of engagement in HIV care, according to a report published on Oct. 13, 2015 in the journal Clinical Infectious Diseases.

A significant proportion of patients that are diagnosed with HIV do not initiate therapy within three months of diagnosis. Even among those who keep their first appointments with HIV care, some do not attend follow-up appointments. Others only adhere to therapy intermittently.

Dr. Maunank Shah, the lead author and assistant professor of medicine at the Johns Hopkins School of Medicine, devised a computer model of HIV transmission in the U.S. with his colleagues. This model helps to address the extent to which suboptimal engagement in HIV care hinders the control of the HIV epidemic in the U.S. and to estimate the epidemiological and economic consequences of incomplete engagement in HIV care. The investigators constructed a model of HIV transmission among U.S. adults aged 15 to 65 years over a projected 20-year period assuming the continuation of current trends.

Without the implementation of further interventions, 1.39 million new HIV infections and 435,000 AIDS-related deaths are estimated to occur, costing $256 billion over the next 20 years. Using this data as a control, the investigators examined how HIV incidence, mortality, healthcare costs and quality-adjusted life years (QALYs) can be affected by interventions such as enhanced screening programs.

Annual testing for high-risk individuals would prevent 215,000 new HIV infections at a cost of $49.2 billion over the next 20 years, which is equivalent to $84,700 per QALY according to the model. If annual testing for high risk-individuals were combined with screening of the general population between the ages of 25 and 65 every three years, 11,600 additional infections would be averted at a cost of an additional $21.9 billion. Enhanced screening policies alone are expected to produce such improvements and thwart a predicted 18 to 21 percent of AIDS-related deaths.

If other interventions aside from enhanced HIV screening are introduced along the HIV continuum of care, outcomes are estimated to improve. When annual testing for high-risk individuals is combined with a shift from 70 percent to 90 percent of HIV patients receiving access to care, an estimated 292,000 HIV infections could be prevented at a cost-effectiveness ratio of $65,700 per QALY gained. A 50 percent reduction in the annual rate of disengagement from care along with a 50 percent increase in the yearly rate of re-engagement in care is estimated to result in the aversion of 494,000 HIV infections at a cost of $33,700 per QALY even at current levels of linkage to care.

The investigators also considered a combination of programs that would encompass annual testing for high-risk groups, improved linkage to care, enhanced retention and enhanced re-engagement in care. Their model estimates that this package of interventions would avert 752,000 new HIV infections at a cost of $96 billion. In other words these interventions would reduce HIV incidence by 54 percent and mortality rate by 64 percent at $45,300 per QALY. The combination of enhanced targeted screening and reformed measures to improve engagement in care have been noted among other possible interventions as the most beneficial methods with a relatively low cost-effectiveness ratio.

The investigators acknowledge the limitations of their modeling analysis, which broadly captures the cost-effectiveness of specific interventions at a national rather than a local level. However as the model used a fixed time period of the next 20 years to estimate costs and effects, the data produced by this study are most likely conservative estimates of the cost-effectiveness of the interventions.

Further studies are needed to corroborate the findings of this study. According to researchers, prior inquiries have also demonstrated that expanded HIV-screening programs and earlier treatment initiation are cost-effective. However such interventions are limited if they are implemented alone and without additional programs that promote linkage to and engagement in HIV care. Reducing the drop-offs along the HIV care continuum can have a significant national epidemiologic and economic impact.

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