Abstract
Since 2014, the recommended laboratory testing algorithm for diagnosing human immunodeficiency virus (HIV) infection has included a supplemental HIV-1/HIV-2 differentiation test to confirm infection type on the basis of the presence of type-specific antibodies (1). Correctly identifying HIV-1 and HIV-2 infections is vital because their epidemiology and clinical management differ. To describe the percentage of diagnoses for which an HIV-1/HIV-2 differentiation test result was reported and to categorize HIV type based on laboratory test results, 2010-2017 data from CDC's National HIV Surveillance System (NHSS) were analyzed. During 2010-2017, a substantial increase in the number of HIV-1/HIV-2 differentiation test results were reported to NHSS, consistent with implementation of the HIV laboratory-based testing algorithm recommended in 2014. However, >99.9% of all HIV infections identified in the United States were categorized as HIV-1, and the number of HIV-2 diagnoses (mono-infection or dual-infection) remained extremely low (<0.03% of all HIV infections). In addition, the overall number of false positive HIV-2 test results produced by the HIV-1/HIV-2 differentiation increased. The diagnostic value of a confirmatory antibody differentiation test in a setting with sensitive and specific screening tests and few HIV-2 infections might be limited. Evaluation and consideration of other HIV tests approved by the Food and Drug Administration (FDA) that might increase efficiencies in the CDC and Association of Public Health Laboratories-recommended HIV testing algorithm are warranted.
Highlights
CDC recommends that laboratories continue to follow the laboratory-based algorithm with the HIV-1/HIV-2 differentiation test as the second step
HIV-2 infection results in lower levels of circulating virus compared with those of HIV-1 infection
Evidence of pregnancy in women with HIV infection is underreported to National HIV Surveillance System (NHSS) [10]. This can result in an underestimation of the number of pregnant women with HIV-2, reporting of perinatal HIV infection is robust, increasing the likelihood that perinatal HIV-2 infection would have been recognized
Summary
Trends in HIV-2 Diagnoses and Use of the HIV-1/HIV-2 Differentiation Test — United States, 2010–2017. CDC developed a surveillance definition for HIV-2 to determine the number of such cases and to describe the demographics of persons identified with the different HIV infection types in the United States. For this analysis, the surveillance definitions for type of HIV infection include 1) HIV-2 mono-infection, defined as having an HIV-2-positive nucleic acid test (NAT) result or an HIV-2-positive HIV-1/HIV-2 differentiation test result and no evidence of HIV-1-RNA or DNA*; 2) HIV-1 and HIV-2 dual-infection, defined as having an HIV-2-positive or HIV-1-positive and HIV-2-positive antibody test result and positive HIV-1 and HIV-2 RNA or DNA test results; or 3) probable HIV-2 infection, defined as having an HIV-2-positive antibody test result (HIV-2 immunoassay or an HIV-1/HIV-2 antigen and antibody test) and no evidence of HIV-1 RNA or DNA.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
