Nurse practioner at HIV docs office confirmed that flu shot can give false positive or intermediate results on antibody tests . Because most free clinics only give Elisas and instant tests other options are unavailable unless one wants to be identified by doctor visit and test Western Blot of Viral load . So, exactly how long after the flu shot is it safe to take Elisa or rapid tests without false positives outcomes ?
There is no "exact" time, as immune integrity and immune response very considerably from person to person.
I would not put off HIV testing due to seasonal flu vaccination. In the small number of cases in which an indeterminate or false-positive screening antibody test results from cross-reacting antibodies induced by a vaccination, follow-up, more sophisticated testing will quickly identify the false/indeterminate result and confirm HIV-negative status. If, on the other hand, the person getting tested is truly HIV infected, it greatly behooves him or her to know as soon as possible so that appropriate management can be started quickly.