COVID-19 vaccine-associated myositis: a comprehensive review of the literature driven by a case report

Several cases of vaccine-associated manifestations have been published including cases of inflammatory myositis. Herein, we comprehensively review the literature on the occasion of case of a woman with inflammatory myositis following COVID-19 vaccination. A 67-year-old woman presented with left arm edema, rash, and weakness after the 2^nd dose of the BTN162b2 vaccine. Raised muscle enzymes and inflammatory markers with muscle edema on MRI and myositis findings on the electromyogram established the diagnosis. She was successfully treated with methylprednisolone pulses, intravenous immunoglobulin, methotrexate, and hydroxychloroquine. Cases of inflammatory myositis, dermatomyositis, or interstitial lung disease with myositis-specific autoantibodies or myositis-associated autoantibodies within 12 weeks from SARS-CoV-2 vaccination were included. Cases with malignancy, prior or subsequent COVID-19 infection, preexisting myositis/interstitial lung disease (ILD)/dermatomyositis (DM), or other connective tissue diseases were excluded. From our search, 49 cases were identified (mean age: 56.55 + 17.17 years), 59% were women, while 12 patients received the ChAdOx1 vaccine, 27 the BNT162b2, 8 the mRNA-1273, 1 the DB15806, and 1 the Ad26.COV2.S (overall, 70% received mRNA vaccines). Muscle involvement was the most common manifestation (79.5%), followed by skin involvement (53%) and ILD (34.6%), which were more common in the m-RNA vaccinees. Muscle biopsy, MRI findings, and autoantibody profile varied significantly, while successful immunosuppressive treatment was applied in most cases. Inflammatory myositis after COVID-19 vaccination has been well documented worldwide. Current evidence in support of a pathogenic link is challenging due to significant variation in clinical manifestations, radiological, histopathological, and immunological features.