Cytological changes in the urine in the form of inclusion-bearing cells, giant cells and haematuria after vaccination with inactivated influenza virus vaccine. A study with application of Millipore procedure and Papanicolaou staining.

Marked cellular reactions in the urine appeared after subcutaneous vaccination with inactivated influenza virus vaccine. Inclusion-bearing epithelial cells increased in 16 cases from 2.4 to 9.6% and erythrocytes from 2.5 to 16.2 per visual field. Pathological values for inclusion-bearing cells were found in 5 of 18 cases (28%), spherical giant cells in 3 (17%), and an abnormal number of erythrocytes in 7 (39%). Killed virus, lacking the capability of replication, thus gave rise both to the formation of inclusions and to fusion of cells within the epithelium of the kidneys and of the urinary tract, and also to haematuria. There was a striking resemblance to the reaction in 34 cases of uncomplicated influenza A2, but the inclusion-provoking effect of the vaccination dose was clearly weaker and the erythrocyturia somewhat less pronounced. As a rule the cellular changes after the vaccination quickly reverted to normal, but there were examples of elevated values still existing after 6 months. Two patients had a high inclusion content and haematuria persisting for 3 and 4 years, one of whom following influenza A2. Influenza and influenza vaccinations may be the cause of certain instances of chronic benign haematuria.