Clinical factors associated with the humoral immune response to influenza vaccination in chronic obstructive pulmonary disease

Background and objective: Individuals with chronic obstructive pulmonary disease (COPD) are at a high risk of developing signifcant complications from infection with the influenza virus. It is therefore vital to ensure that prophylaxis with the influenza vaccine is effective in COPD. The aim of this study was to assess the immunogenicity of the 2010 trivalent influenza vaccine in persons with COPD compared to healthy subjects without lung disease, and to examine clinical factors associated with the serological response to the vaccine. Methods: In this observational study, 34 subjects (20 COPD, 14 healthy) received the 2010 infu-enza vaccine. Antibody titers at baseline and 28 days post-vaccination were measured using the hemagglutination inhibition assay (HAI) assay. Primary endpoints included seroconversion ($4-fold increase in antibody titers from baseline) and the fold increase in antibody titer after vaccination. Results: Persons with COPD mounted a significantly lower humoral immune response to the infuenza vaccine compared to healthy participants. Seroconversion occurred in 90% of healthy participants, but only in 43% of COPD patients (P=0.036). Increasing age and previous influ-enza vaccination were associated with lower antibody responses. Antibody titers did not vary significantly with cigarette smoking, presence of other comorbid diseases, or COPD severity. Conclusion: The humoral immune response to the 2010 influenza vaccine was lower in persons with COPD compared to non-COPD controls. The antibody response also declined with increasing age and in those with a history of prior vaccination.