Immunogenicity and safety of vaccination in children with paediatric rheumatic diseases: a scoping review.

Children with paediatric rheumatic diseases (PRDs) are at increased risk of vaccine-preventable disease. Safe and effective vaccination is central to preventive care in PRD patients; however, uncertainty surrounding immunogenicity and safety has contributed to suboptimal vaccination. The aim of this study was to evaluate treatment effect on immunogenicity to vaccination in PRD patients and assess vaccine safety, specifically adverse events following immunisation (AEFI) and disease flare. Scoping review. In this scoping review, a systematic search of PubMed, CINAHL and Embase databases was conducted from 2014 to 23 August 2022 to identify observational studies evaluating the immunogenicity and safety of commonly used vaccinations in PRD patients. The primary outcome was immunogenicity (defined as seroprotection and protective antibody concentrations), with secondary outcomes describing AEFI and disease flare also extracted. Due to extensive heterogeneity related to diagnostic and vaccination variability, narrative synthesis was used to describe the findings of each study. Study quality was assessed via the Mixed Methods Appraisal Tool. The review was prospectively registered with PROSPERO (CRD42022307212). The search yielded 19 studies evaluating immunogenicity to vaccination and incidence of AEFI and disease flares in this population, which were of acceptable quality. Corticosteroids did not have deleterious effects on vaccine response. Treatment with conventional disease-modifying antirheumatic drugs (DMARDs) and biologic DMARDs generally had no effect immunogenicity in PRD patients. While patients exhibited adequate seroprotection, protective antibody levels were lower in patients on some immunosuppressant agents. Varicella infections were recorded post vaccination in several patients with low protective antibody levels undergoing treatment with DMARDs and corticosteroids. Most vaccines appear safe and effective in PRD patients, despite immunosuppressant treatment. Booster vaccinations should be considered with some studies highlighting inadequate seroprotection following primary course of vaccinations with acceleration of antibody decline over time. There was limited evidence to support avoiding live vaccines in PRD patients.