Polymyalgia rheumatica and polymyalgia-like syndromes as adverse events following COVID-19 vaccines: working notes from a narrative review of published literature

Since the 1990s, polymyalgia rheumatica (PMR) has been reported as a possible adverse event following immunization (AEFI). The aim of this narrative review is to provide an overview of PMR (and PMR-like syndromes) following the most common types of COVID-19 vaccines, namely mRNA (tozinameran and mRNA-1273) and adenovirus-vectored (ChAdOx1-S) vaccines. To date, published literature reports few cases of PMR as vaccine-linked AEFI. Yet Vigibase, the WHO pharmacovigilance database, reports a few hundred cases. Based on these data, we address the question whether PMR/PMR-like syndromes following COVID-19 vaccines can be a true adverse or a coincidental event, and discuss its possible pathogenetic mechanisms.