Detection of influenza antigen with rapid antibody-based tests after intranasal influenza vaccination (FluMist).

Rapid tests for influenza antigen detection are frequently used, but it is not known how receipt of intranasal influenza vaccine affects results of these tests. We tested healthy adults who received either intranasal or intramuscular influenza vaccine. Of the 14 intranasal vaccine recipients, 7 (50%) had a direct fluorescent antibody test (DFA) result and 2 (14%) had an enzyme immunoassay (EIA) result that was positive for influenza antigen within 7 days after vaccination.