Background Vaccine administration is an effective tool to prevent infectious diseases. Patients with autoimmune diseases have a higher risk of infections -mainly at respiratory level- as a consequence of immune system dysregulation as well as of immunosuppressive treatment. Therefore, prevention by specific available vaccinations is crucial, as suggested by different studies and by EULAR and ACR recommendations. To date, literature data support the effectiveness of vaccinations with pneumococcal polysaccharide vaccine in patients with Rheumatoid Arthritis (RA); on the contrary, the 13-valent conjugate pneumococcal vaccine has not yet been studied in RA patients receiving immunosuppressive treatment.
Objectives The aim of this study was to evaluate the immunogenicity of the 13-valent conjugate pneumococcal vaccine in patients with RA receiving Methotrexate (MTX)+TNF blockers, MTX alone or TNF blockers monotherapy compared to healthy controls (HC). The secondary objective was to determine vaccine safety.
Methods Consecutive RA patients with low-moderate disease activity treated with stable dose of glucocorticoids, MTX and/or anti-TNF drugs were enrolled. The pneumococcal vaccine was administered intramuscularly at baseline visit; patients underwent clinical and laboratory evaluation at the time of vaccination (T0) and after 1 (T1) and 6 (T2) months. Blood samples for the evaluation of specific anti-pneumococcal antibodies were collected at the same time-points. The immunogenicity was evaluated with the enzyme-linked immunosorbent assay (ELISA). Data were expressed as mean ± standard deviation; t-test was used to evaluate the difference in serum levels of antibodies to pneumococcal antigens at 1 and 6 months compared to baseline values. A p value <0.05 was considered statistically significant.
Results 38 patients [36F/2M, age 62.1±11 yrs] and 6 healthy controls [2F/4M age 63.7±2 yrs] were enrolled; 11 patients were treated with MTX alone, 12 with TNF blocking monotherapy (Etanercept n=7, Adalimumab n=3 and Certolizumab n=2) and 15 with MTX in combination with TNF blockers (Infliximab n=1, Etanercept n=6, Adalimumab n=6 and Golimumab n=2). Actually, 24 patients and 3 HC have completed 6 months of follow-up. More than half of patients (61%) developed a positive antibody response to the thirteen polysaccharides (twofold increase of antibody titer). The most immunogenic pneumococcal antigens were polysaccharides 1, 4 and 9V (Image 1). At 1 month a threefold increase in antibody titre with a protective level maintained throughout 6 months was observed. After 1 and 6 months of treatment, no significant change in DAS28 was observed in vaccinated patients. During the follow-up we did not observe any severe adverse reactions in RA patients nor in healthy controls. Mild systemic and local adverse events (redness and/or swelling of injection site) were reported by 44% of vaccinated RA patients and by 16% of healthy subjects.
Conclusions This is the first preliminary study to demonstrate safety and immunogenicity of the 13-valent conjugate pneumococcal vaccine in RA patients on immunosuppressive treatment.
Disclosure of Interest None declared