Background Varicella zoster virus (VZV) infection is a serious preventable infection in patients receiving immunosuppression. The safety of varicella vacination (VV) in patients with paediatric rheumatic disease (PRD) while receiving immunosuppression (IS) has been debated.
Objectives To evaluate the safety of 1st and/or 2nd dose varicella vaccine (VV) in patients (pts) with PRDs receiving IS after passing a pre-vaccination check list of immunologic criteria.
Methods In this single centre study, 21 VZV-susceptible pts with clinically inactive PRDs, including different categories of juvenile idiopathic arthritis and connective tissue diseases between the ages of 2–18 years on low-intensity IS (LIIS) (methotrexate [MTX] ≤15mg/m2/week and/or prednisolone <10mg/day) or high-intensity IS (HIIS) (MTX>15mg/m2/week, leflunomide, mycophenolate mofetil [MMF], etanercept, tocilizumab, anakinra, abatacept, or a combination thereof) were included in this study. Prior to vaccination, pts were screened according to an immunologic checklist with predefined cut-offs (for pts on LIIS: WBC>3000/μl, ALC>1200/μl, IgG>500mg/dl, IgM>0, Tetanus toxin-IgG >0,10IU/ml; in addition, for pts on HIIS: CD4 >200/μl [if>5 yrs] or CD4 >500/μl [if 1-5 yrs] and positive T cell reactivity to mitogen or antigen, e.g. via TB-EliSpot positive control. Pts meeting these safety criteria received either a 1st and/or 2nd dose of VV without suspension of IS. VZV-IgG levels were measured before applying VV and after each dose. VZV cellular mediated immunity (CMI) was measured after VV. Potential side effects and PRD flares were monitored.
Results Out of 9 pts receiving LIIS and 12 pts receiving HIIS none failed the immunologic checklist. 8 pts (2 LIIS, 6 HIIS) had already received their 1 dose of VV prior to this study and received a 2nd/booster dose of VV only. 13 pts (7 LIIS, 6 HIIS) received their 1st dose of VV within the study and 7 of these 13 pts received a 2nd dose of VV. 11/13 pts demonstrated VZV-IgG levels of >150 IU/ml after the 1st dose of VV, and 5/7 pts of those receiving a 2nd dose of VV achieved levels of >500 IU/ml. 1 pt (on MMF) did not achieve protective VZV-IgG levels and 1 pt (on leflunomide and abatacept) did just achieve a VZV-IgG level of exactly 150 IU/ml, despite 2 doses of VV and adequate humoral and cellular immunity. Of those 8 pts receiving a booster dose only, all exceeded VZV-IgG levels of >500 IU/ml by far. There was no difference in either the mean absolute or relative increase (Δ) in VZV-IgG between pts on LIIS vs. HIIS (after 1st dose of VZV Δ341 IU/ml vs. Δ378 IU/ml and 4.7-fold vs. 4.2-fold, respectively; after 2nd dose Δ745 IU/ml vs. Δ1001 IU/ml and 6.9-fold vs. 6.4-fold, respectively). Data on VZV-CMI were pending at the time of abstract submission. There was no evidence of VV-induced varicella or other VV-associated complications. None of the pts developed a PRD flare and no change in the IS regimen was required in any pt during a minimum follow-up of 4 wks. 7 pts had transient arthralgias of unclear association with VV administration.
Conclusions After meeting easy-to-obtain immunologic criteria, the VV could safely be applied to a diverse cohort of pts with clinically inactive PID on IS with excellent response in the majority of pts.
Acknowledgements Supported by a grant from “Verein Hilfe für das rheumakranke Kind”.
Disclosure of Interest None declared