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Published on: September 6, 2019
Young age a predictor of weak reactivity in a rapid antibody test in infants infected with HIV
Leana Maree1, Gert U van Zyl, Shelley L Lotter
1Division of Medical Virology, Department of Pathology, National Health Laboratory Service, University of Stellenbosch, Cape Town, South Africa. leana@sun.ac.za
Insights
Rapid HIV antibody tests show high false-negative rates in infants due to young age, not other factors. Caution is advised when using adult-validated rapid assays for infant HIV diagnosis.
Area of Science:
- Immunology
- Virology
- Pediatric Infectious Diseases
Background:
- Resource-constrained settings often rely on rapid antibody tests for infant HIV screening.
- Previous studies indicate a high false-negative rate of rapid HIV assays in infants.
- The Capillus HIV-1/HIV-2 test is a commonly used rapid antibody assay.
Purpose of the Study:
- To identify predictors of low or negative antibody reactivity in infants using the Capillus HIV-1/HIV-2 assay.
- To investigate factors such as CD4 count, HIV-1 viral load, and antigen-specific reactivity.
- To determine if age is a significant factor in assay performance.
Main Methods:
- Analysis of CD4 (+) count and percentage.
- Measurement of HIV-1 viral load.
- Assessment of antigen-specific reactivity.
- Exploration of age as a predictor of assay results.
Main Results:
- Young age was the only significant predictor of low antibody reactivity.
- This age-related phenomenon was specific to HIV antibody response.
- No similar age association was observed for antibody reactivity to tetanus toxoid.
Conclusions:
- Rapid HIV antibody assays validated in adults may yield high false-negative rates in young infants.
- Age is a critical factor influencing the reliability of rapid HIV testing in pediatric populations.
- Clinical use of these assays in infants requires extreme caution and consideration of potential age-related limitations.
Abstract:
In a resource-constrained African setting, children suspected of being infected with HIV are often screened with rapid antibody tests prior to definitive diagnosis with viral genome detection. It has previously been shown that a rapid antibody assay such as the Capillus HIV-1/HIV-2 test may have a high false-negative rate in infants. In this study CD(4) (+) count and percentage, HIV-1 viral load, antigen-specific reactivity, and age was explored as predictors of negative or low antibody reactivity by this assay. Young age was found to be the only factor associated significantly with low antibody reactivity. This phenomenon appeared to be specific to HIV since no such age association was found for antibody reactivity to tetanus toxoid. Rapid assays only validated in adults should therefore be used with utmost caution in young infants since this may lead to high rates of false-negative results.
