ANNUAL INFLUENZA VACCINATION - IMMUNE-RESPONSE IN PATIENTS OVER 10 YEARS

Objective: To determine the effect of repeated annual influenza immuni zation on the host's serum antibody. Design: Ten year observational st udy with cohort design. Setting: Cystic Fibrosis Center at St. Vincent 's Hospital and Medical Center, New York City, NY. Patients: thirty-ei ght children and young adults with cystic fibrosis (CF). Measurements: Serum hemagglutination inhibition (HI) antibody titers were determine d at the time of vaccination and 4 weeks later each year in the fall b efore the influenza epidemic. Shwachman scores were determined each ye ar. Results: While the pre-vaccination and post-vaccination geometric mean serum HI antibody titers varied from year to year, no upward or d ownward trend was evident over the 10 year period. The reciprocal of t he post-vaccination geometric mean HI titers ranged annually from 32 t o 74 for the influenza A (H3N2) vaccine strains, from 53 to 133 for th e influenza A (H1N1) strains, and from 18 to 174 for influenza B strai ns. In addition, the majority of vaccinees had a presumably protective post-vaccination serum HI titer greater than or equal to 1:40 each ye ar for all three vaccine strains. The initial mean Shwachman score of the group was 77. The final score of 76 after 10 years was not signifi cantly different. Conclusions: Annual influenza vaccination appears to regularly induce presumably protective serum antibody levels in most CF children and young adults studied over a 10 year period. Copyright (C) 1996 Elsevier Science Ltd.