Ten-Year Follow-Up Study for Safety of Adjuvant 65 Influenza Vaccine in Man

Clinical follow-up was made of more than 2000 persons who had received adjuvant 65 type influenza or aqueous type influenza vaccine or who had served as unvaccinated controls in studies in which vaccines were given up to 10 yr previously. No long-term effect was noted other than the occurrence in no more than 0.8% of persons observed of a persistent nodule that was difficult to palpate and that was no larger than a small pea. The rates for occurrence of nodules in vaccinated persons were not significantly greater than in the unvaccinated controls. There was no significant difference in the percentage of persons who died between the groups for respiratory disease, cardiovascular disease, cancer, or for miscellaneous cause (p > 0.15 for each category by Fisher's exact test). All evidence points to safety of the adjuvant type vaccine both on short- and long-term observation.