Duke University Investigators Create More Accurate HIV Incidence Test

Investigators from the Duke Human Vaccine Institute have developed a binding assay capable of more accurately identifying new versus long-standing HIV infections than currently available assays, which, in turn, could help improve efforts to reduce the incidence of the virus around the world.

“Improved methods for classifying recent infection from older infections are critically needed to help identify the most effective prevention strategies,” said Georgia Tomaras, PhD, professor in the Department of Surgery and director of research at Duke Human Vaccine Institute, and senior author on the study in an official press release and accompanying interview. “This is really important for the field because, in 2016, there were 1.8 million new infections [of HIV]. The field is trying to improve upon prevention modalities, but in order to understand if these prevention modalities are effective, we really need to understand the number of new infections per year.”

According to Dr. Tomaras, the currently available assays are not able to distinguish recent infections from long-standing ones and they have a high false-recent rate, meaning that they misclassify individuals as having recent or long-standing infections. An additional problem with the currently available assays is that they are inaccurately classifying individuals who are taking antiretroviral therapy (ART).

Therefore, the investigators set out to develop a model for measuring HIV incidence that also considers how the virus acts within the body at different stages of infection and with the presence of ART. After performing a retrospective analysis of HIV patients over time to profile the circulating antibody response to HIV, the investigators noticed that antibody responses to the infection appeared sequentially, meaning that a person’s immune response “recognized different parts of HIV, sequentially,” according to Dr. Tomaras. In addition, they noticed that different antibody forms appeared at different time points during infection and that they could “identify the kinetics of those antibody responses coming up that are recognizing the virus, and the maturation of those antibody responses over time.”

The results of their investigation yielded, according to the release, “a [binding] assay that identifies new combinations of naturally occurring antibody biomarkers, resulting in a promising set of 4 biomarkers that could be used. The new assay has a longer, and thus more accurate, time-period that constitutes recent infection, and fewer false classifications.” The new assay is an improvement on previous assays in that it yields a reduced false-recent rate and can determine recent versus long-standing infection in the presence of ART.

The identification of these unique antibodies could aid public health officials in identifying hot spots of new infections, said lead author, Kelly Seaton, PhD, associate research lab manager at Duke, and thus they would be able to better target their efforts. “The improvements seen with this set of biomarkers are a tremendous benefit to the field because they allow for public health researchers and epidemiologists and those treating HIV to more effectively target prevention and treatment strategies,” she said. “By having an accurate handle on the epidemic and where the hotspots are occurring and who is becoming recently infected versus who has been infected for a long time.” In addition, the costs of performing research on the incidence of HIV infections would be reduced as researchers would be able to use a smaller sample size.

The investigators state that the next stage, currently in progress, is the development of a kit that contains the assay that will be put into the hands of those investigators who are already looking at the incidence of HIV at the regional, state, and national levels.