DONOR FOLLOW-UP OF INFLUENZA VACCINE-RELATED MULTIPLE VIRAL ENZYME-IMMUNOASSAY REACTIVITY

False-positive enzyme immunoassay (EIA) tests in blood donors receivin g influenza vaccine were first reported in 1991. We conducted follow-u p testing for 6 months of those donors with multiply reactive, but unc onfirmed EIA (at least 2 positives in anti-HCV-1.O, anti-HIV-1, and an ti-HTLV-I assays) with a history of recent flu vaccine to determine th e duration of false positivity. Of 133,000 donors tested, 16 met study criteria; all 16 were reactive for anti-HCV, 10 were reactive for ant i-HIV-1, and 12 were reactive for anti-HTLV-I. Fifteen donors were ava ilable for follow-up testing (using the original screening and supplem ental tests): 10 (67%) reverted to negative for the 3 tests and 5 rema ined false positive for various markers at last sampling (3-6 months a fter vaccination). The mean duration of false positivity for those rev erting to negative EIA test status, was 4.2 months (range 2-7 months) indicating a transient phenomenon and supporting studies which suggest a role for IgM in the mechanism.