[Determination of antibodies against influenza viruses, using the ELISA method]

A microplate method of enzyme-linked immunosorbent assay (ELISA) was adapted for the demonstration of antibodies to influenza A and B in 25 paired acute and convalescent sera taken from patients with influenza A infection, in 11 single convalescent sera collected from patients with acute respiratory infection and serological evidence of influenza B infection, in 14 paired sera collected from volunteers who were vaccinated with an aqueous inactivated influenza A and B vaccine, and in 15 serum samples from normal subjects. Comparison showed that ELISA was more sensitive than the hemagglutination-inhibition test. The enzyme-immunoassay gave equally reliable and reproducible results and requires very small amounts of antigen and sera. This simple test may be suitable for use in large seroepidemiological surveys.