Image created by Dr. Michael J. Miller
Researchers have developed a fast, accessible test that could significantly reduce the number of false positives associated with standard serological HIV tests. In a study published in Science Advances, the test showed accuracy on par or better than any other existing approaches when distinguishing individuals with an active HIV infection from those who carry antibodies against HIV due to vaccination.
While there is yet no approved vaccines for HIV, development is underway, with multiple vaccine candidates currently under evaluation in clinical trials. Preventive vaccines are often designed to make the immune system produce antibodies against HIV antigens, including core proteins and glycoproteins that form the viral envelope. However, these antibodies are typically the target of standard HIV diagnostic tests, creating an overlap that can result in vaccinated individuals testing positive despite not being actively infected with HIV. This phenomenon is known as vaccine-induced seropositivity (VISP).
“The development of a rapid, affordable and reliable point-of-care diagnostic tool capable of distinguishing immune-induced responses from active HIV infection is essential to support the broader deployment of HIV vaccines and to address the limitations of existing technologies,” said Dipanjan Pan, PhD, professor in nanomedicine, nuclear engineering, and materials science and engineering at Pennsylvania State University. “To address the laboratory testing challenges posed by this problem, we developed a test that simultaneously detects protein and nucleic acid markers within a single device.”
The test developed by Pan and colleagues combines electrochemical sensing technology with machine learning algorithms to provide test results within five minutes. Using a 3D printed device the size of a smartphone, a blood sample taken with a lancet is filtered through four different channels. This allows it to simultaneously detect the p24 HIV protein, antibodies against p24, viral RNA from HIV particles, and a control RNA molecule.
“That’s the key innovation in overcoming the critical limitation of conventional antibody-based diagnostics,” Pan explained. “By incorporating HIV-1 RNA detection, the testing platform provides a definitive indicator of active viral replication, which is absent in VISP cases.”
This prototype device was tested in 104 clinical samples, including vaccinated and unvaccinated HIV-negative patients as well as vaccinated and unvaccinated HIV-positive patients. With the help of AI algorithms, the test delivered quantitative results within five minutes, showing 95% sensitivity and 98% specificity in distinguishing active infection from VISP cases. In addition, the test can estimate whether a patient is experiencing an early- or late-stage infection based on the amount of protein antigens and antibodies detected in the sample.
“Our proposed all-in-one testing platform represents a substantial advancement in HIV diagnostics, enabling accurate detection of active HIV infection while minimizing false positives due to VISP,” said Pan. “The scalable design and relatively low cost of the device make it an appealing solution for widespread adoption in both resource-rich and resource-limited environments.”
As HIV vaccines receive approval and start being used, VISP cases could become a significant challenge, potentially skewing incidence data and complicating the accurate detection of HIV outbreaks. In this setting, the use of standard serological tests could lead to misdiagnoses, causing patients psychological distress and societal challenges, making clinical trial results difficult to interpret, creating barriers for blood and organ donations, and resulting in potential complications with insurance, military service, employment, travel, immigration, or pregnancy.
“Despite continuous advancements in prevention and treatment, HIV remains a significant global health issue,” said Pan. “Developing safe and effective vaccines is crucial for reducing HIV transmission rates and ultimately managing the epidemic.”
Reference
Ketan Dighe et al., Distinguishing active HIV-1 infection from vaccine-induced seropositivity in HIV vaccine trial participants. Sci. Adv.11, eadz5639(2025). DOI:10.1126/sciadv.adz5639
Abstract
Vaccine-induced seropositivity (VISP) causes antibodies produced by HIV-1 vaccines to react with standard serological tests, complicating diagnosis and leading to false positives. To distinguish VISP from true HIV infections, we developed a rapid, multiplexed companion electrochemical assay that integrates a three-dimensional–printed device with screen-printed electrodes coated with antigen, antibody, and methylene blue–labeled antisense oligonucleotide probes. The test delivers quantitative results within 5 minutes with calculated analytical limits of detection of 5.88 picograms per milliliter for p24 antigen, 10.96 picograms per milliliter for anti-p24 antibody, and 1259 copies per milliliter for HIV-1 RNA, with minimal cross-reactivity. Clinical testing with 104 plasma samples obtained from vaccinated/unvaccinated, HIV-positive/negative individuals demonstrated 95% sensitivity and 98% specificity in distinguishing active HIV-1 infection from VISP cases. Receiver operating characteristic analysis produced area under the curve values of 0.9888 for HIV-1 RNA, 0.9705 for anti-p24 antibody, and 0.9356 for p24 antigen. These findings highlight the potential to reduce false-positive results caused by VISP by integrating this diagnostic test in clinical trials and large-scale vaccination programs.