Detection of flavivirus antibodies in human serum by epitope‐blocking immunoassay

Human flavivirus group‐reactive, dengue complex‐reactive, and encephalitis virus complex‐reactive antibodies were detected using epitope‐blocking immunoassays in which the binding of selected mouse monoclonal antibodies to flavivirus antigens was blocked by human serum. When late (> 6 months after illness) convalescent sera were tested, the epitope‐blocking immunoassays were superior to the hemagglutination inhibition test and comparable to the plaque reduction neutralization for identifying subjects immune to dengue, to Japanese encephalitis, or both viruses.