Elderly-onset inflammatory myopathy associated with Sjögren's syndrome following SARS-CoV-2 vaccination

As vaccination against SARS-CoV-2 has progressed, various autoimmune diseases, including inflammatory myopathies, have been reported to develop after vaccination. Sjögren's syndrome (SS) sometimes presents as extra-glandular manifestations including inflammatory myopathy. In this report, we describe a case of inflammatory myopathy associated with SS that occurred in an atypically elderly patient after receiving the first dose of the SARS-CoV-2 mRNA vaccine (BNT162b2). The inflammatory myopathy was pathologically classified into non-specific myositis and characterised by predominant infiltration of the B cell lineage in this case. Combined treatment with glucocorticoid, intravenous immunoglobulin, and immunosuppressant resulted in an improvement in swallowing function and muscle strength. While we recognise the efficacy and safety of SARS-CoV-2 vaccines, we also emphasise the importance of recognising that individuals with an immunogenetic predisposition such as positivity of anti SS-A antibody may show disease activity including inflammatory myopathy following vaccination in SS, even at an atypically old age.