Antibody responses to influenza vaccine in patients on biological therapy: Results of RIER cohort study

Abstract Background and objectives Influenza vaccine is recommended for patients with autoimmune inflammatory rheumatic diseases who receive biological therapy. To evaluate if biological therapy impairs immunization after seasonal influenza vaccine. Material and methods Patients with inflammatory arthopathies, psoriasis, inflammatory bowel disease or connective tissue diseases who were receiving or were going to initiate biological therapy were included and vaccinated during 2014–2015 influenza season. ELISA was used to measure influenza antigen A and B antibodies, before and after vaccination. Demographic parameters, diagnosis and kind of treatment were recorded and their influence on the final serological status against influenza was studied. Results 253 subjects were analyzed. After vaccination, 77% of participants presented detectable antibodies against antigen A and 50.6% of them had detectable antibodies against antigen B. Final seropositivity rate against antigen B antibodies increased from baseline (50.6% vs 43.5%, p p  = 0.020). Vaccine response in the rituximab group tended to improve when the interval between the drug administration and the vaccination was at least 12 weeks (seropositivity rate 80.0% in those with the longer interval vs 25.0% in the other group, p=0.054). Conclusions Among the patients on biological therapy vaccinated against influenza, anti-TNF therapy was identified as a predictive factor of final seropositivity. Rituximab presented a lower rate of final seropositivity, which could be increased with an accurate administration schedule.