S100B and HIV infectious disease: Performance of a DHIVAx assay, more specifically a double-antigen bridging (sandwich) ELISA combining the polypeptide antigens gp41e, p31, p17, and Nef, was assessed in 600 individuals with known HIV infection and resulted in a specificity of 98.1% (95% CI: 93.5% to 99.7%) in healthy controls (97.1% [95% CI: 91.8% to 99.2%] at 12 weeks after vaccination) and a sensitivity of 98.5% (95% CI: 97.2% to 99.2%; Fig. 2A).