RESUMO
AIM: To study the hypothesis that COPD patients who do not achieve seroprotective levels after influenza vaccination, are a less immune-competent group with a higher risk of morbidity and mortality. METHODS: 578 patients included in the COMIC cohort had pre- and post-vaccination stable state blood samples in which influenza-vaccine specific antibodies were measured. Post-vaccination titers of ≥40 were considered protective and indicative of being immuno-competent. Primary outcome was all-cause mortality. Morbidity was defined as time till first severe acute exacerbation in COPD (severe AECOPD) and time till first community acquired pneumonia (CAP). RESULTS: 42% of the patients achieved seroprotective levels to both H1N1 and H3N2 after vaccination. Seroprotective levels to H3N2 were markedly higher (96%) than to H1N1(43%). Having seroprotective levels to both H1N1 and H3N2 was not associated with less morbidity (severe AECOPD HR 0.91 (95% 0.66-1.25; p = 0.564) (CAP HR 1.23 (95% 0.75-2.00; p = 0.412)) or lower mortality (HR 1.10(95% 0.87-1.38; p = 0.433)). CONCLUSION: In a large well-characterized COPD cohort only the minority of patients achieved seroprotective titers to H1N1 and H3N1 after the yearly influenza vaccination. While achieving seroprotection after vaccination can be considered a surrogate marker of being immunocompetent, this was not associated with lower morbidity and mortality. Whether this means that the immune status is not a relevant pheno/endotype in COPD patients for the course of their disease or that seroprotection is not an adequate (surrogate) marker to define the immune status in COPD needs to be further studied.
