The complexity of immunology: a rare adverse event following a Pfizer-BioNTech vaccine booster shot.

Several mRNA vaccines have been developed to tackle the global pandemic. Despite their remarkable clinical efficacy, they are not devoid of severe short- and long-term adverse events. In this paper, we describe a rare delayed adverse event (arterial and venous renal thrombosis with myocardial injury) in an otherwise healthy adult female, which occurred three months after she received a booster shot of Pfizer COVID-19 vaccine.  The patient was successfully treated for subacute renal ischemia with intra-arterial urokinase, and her myocardial injury was diagnosed with imaging (contrast-enhanced thoracic CT and cardiac magnetic resonance) and percutaneous coronary intervention. Deferred post-vaccine myocarditis was diagnosed and resolved with steroid therapy. In this paper, we report a useful clinical case for the pharmacovigilance database. Although scientific evidence confirms that the benefits of vaccination far outweigh the risk of adverse events, we would like to point out how important watchful observation is in the medium and long term, especially when the subject belongs to a specific risk category.