Kinetics of anti-ZIKV antibodies after Zika infection using two commercial enzyme-linked immunoassays

High performance assays are essential for the serological diagnosis of recent and past Zika virus (ZIKV) infections but few are presently available. We used two commercially available NS1 antigen-based enzyme-linked immunoassays to study the kinetics of anti-ZIKV IgM and IgG in 15 ZIKV-infected patients for up to 180 days after clinical onset. The Diapro assay detected anti-ZIKV IgM reactivity more frequently (100%) and for longer (median 53 days) than did the Euroimmun assay (60%; 13 days, P < 0.005). Both assays detected anti-ZIKV IgG reactivity 11 days after clinical onset in all subjects. ZIKV IgG reactivity decreased in 3 subjects, suggesting long-term false-negative results with the Euroimmun assay. Existing anti-Dengue antibodies seem to modify the detection of ZIKV IgG but the specificity of the immunoassays was not assessed. These enzyme-linked immunoassays were user-friendly and provided results rapidly in our hands but they need further assessment before being widely used for diagnosis or public health surveys.