Author Interviews, CDC, JAMA / 16.02.2016
New Test Can Improve Detection of Early, Acute HIV Infections
MedicalResearch.com Interview with:
Philip J. Peters, M.D.
HIV Testing and Biomedical Interventions Activity Lead
Epidemiology Branch
CDC’s Division of HIV/AIDS Prevention
Medical Research: What is the background for this study? What are the main findings?
Dr. Peters: Acute HIV infection contributes disproportionately to HIV transmission and identifying individuals with acute HIV infection is critical to prevent further HIV transmission, as diagnosis can lead to several effective HIV prevention interventions. Acute HIV infection can be diagnosed with assays that detect either HIV RNA (the reference standard) or the p24 antigen (an HIV core protein), which are both detectable early after HIV infection and before an antibody response develops. HIV immunoassays that detect both the p24 antigen and anti-HIV antibody (fourth generation antigen/antibody [Ag/Ab] combination immunoassays) are currently being implemented as the initial screening test in the 2014 CDC and American Public Health Laboratories (APHL) recommended HIV diagnostic algorithm. In a prospective study we evaluated the performance of an HIV Ag/Ab combination assay to detect acute HIV infection compared with pooled HIV RNA testing in a high-prevalence population.
All participants were first screened with a rapid HIV test to detect established HIV infection (antibody detectable). All participants with a negative rapid HIV test result were then screened for acute HIV infection with an HIV Ag/Ab combination assay (index test) and pooled HIV-1 RNA testing. HIV RNA testing was the reference standard, with positive reference standard result defined as detectable HIV-1 RNA on an individual RNA test.
Among 86,836 participants with complete test results (median age, 29 years; 75.0% male; 51.8% men who have sex with men), acute HIV infection was diagnosed in 168 (0.19%). Acute HIV infection was detected in 134 (0.15%) participants with HIV Ag/Ab combination testing (acute HIV infection sensitivity, 79.8%) and in 164 (0.19%) with pooled HIV RNA testing (sensitivity, 97.6%; sensitivity comparison, p<0.001). Overall HIV Ag/Ab combination testing detected 82% of acute HIV infections detectable by pooled HIV RNA testing. Compared with rapid HIV testing alone (which detected established HIV infection), HIV Ag/Ab combination testing increased the relative HIV diagnostic yield (both established and acute HIV infections) by 10.4% and pooled HIV RNA testing increased the relative HIV diagnostic yield by 12.4%.
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