FRI0213 The Association between Antibody Levels before and after 7-Valent Pneumococcal Conjugate Vaccine Immunization and Subsequent Pneumococcal Infection in Arthritis Patients
Authors: J. Nagel, P. Geborek, T. Saxne, G. Jönsson, M. Englund, I. Petersson, J.-Å. Nilsson, M. Crnkic Kapetanovic
Journal: Annals of the Rheumatic Diseases (2014)

<h3>Background</h3> Antibody response after vaccination is a surrogate measure of vaccine efficacy. Studies exploring the association between post-vaccination antibody levels and protection against infections after immunization with pneumococcal conjugate vaccine in adult patients with arthritis are lacking. <h3>Objectives</h3> To investigate the association between antibody response after vaccination and occurrence of putative pneumococcal infections up to 53 months after vaccination with 7-valent pneumococcal conjugate vaccine (PCV7) in patients with rheumatoid arthritis (RA) and spondylarthropathy (SpA). <h3>Methods</h3> A cohort of 497 patients with rheumatoid arthritis (RA; n=248) and spondylarthropathy (SpA; n=249) including psoriatic arthritis, regularly followed at the outpatient rheumatology clinic, Skåne University Hospital in Lund and Malmö, was immunised with a single dose of PCV7. At vaccination, patients were treated with methotrexate (MTX) (n=84), anti-TNF+MTX (n=169) or anti-TNF as monotherapy (n=158) or NSAIDs/analgesics (only SpA patients; n=86). Antibody levels for 6B and 23B were measured before and 4-6 weeks after vaccination using ELISA. Positive antibody response was defined as ≥2-fold increase in pre-vaccination antibody levels. Vaccinated patients with a history of putative serious pneumococcal infections were identified in the Skåne Healthcare Register using ICD-10 diagnostic codes. Serious infections included: pneumonia, other lower respiratory infections, meningitis, sepsis and septic arthritis. All events occurring up to 4.5 years after vaccination were retrieved. Relation between post-vaccination antibody levels and severe infection was explored using relation receiver operating characteristic (ROC) curves for each serotype separately. <h3>Results</h3> Results. Between May 2008 and December 31st 2012 in total 27 serious infections were identified in 23 patients (4.6%) (4 patients had 2 infections). Geometric mean titers (GMT) for 6B and 23F were calculated using logarithmic transformed pre- and post-vaccination antibody titers (Table). Patients with serious infections had significantly lower post-vaccination antibody titers for both serotype 6B (p=0.040) and 23F (0.036; Mann Whitney <i>U-</i>test). ROC curves identified cut-off levels of 1.17 mg/L (70% specificity and 39% sensitivity) for serotype 23F and 1.23 mg/L (76% specificity and 35% sensitivity) for serotype 6B. <h3>Conclusions</h3> Patients with a history of a serious infection after vaccination had lower antibody levels compared to those without such infections. Cut-off levels of post-vaccination antibody titers associated with protection for serious infections corresponded to those of ≥1 mg/L being generally considered as protective at our laboratory. Frequency of positive antibody response to vaccination did not differ between patients with and without serious infections. <h3>Disclosure of Interest</h3> None declared <h3>DOI</h3> 10.1136/annrheumdis-2014-eular.3786