Delayed Extensive Local Reactions: A Case Series to the mRNA-1273 Vaccine Against SARS-CoV-2

• Published in: Drug safety 2021-12, Vol.44 (12), p.1410-1410
• Main Authors: Da Silva, R Ferreira, Ribeiro-Vaz, I, Silva, A M, Guedes, P, Morato, M, Polonia, J Junqueira
• Format: Article
• Language: English
• Subjects: Adverse events; Antibiotics; Antihistamines; Coronaviruses; Corticosteroids; COVID-19; COVID-19 vaccines; Cryotherapy; Dictionaries; Edema; Erythema; Health services; Hypersensitivity; Hypersensitivity (delayed); Immunization; Medical treatment; mRNA; mRNA vaccines; Nonsteroidal anti-inflammatory drugs; Pain; Patients; Pharmacovigilance; Pruritus; Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; Signs and symptoms; Swelling; Vaccines; Viral diseases
• ISSN: 0114-5916; 1179-1942

Background/Introduction: Adverse events following immunisation (AEFIs) are unpleasant/unintended medical occurrences (sign, symptom, laboratory finding, disease) observed after immunisation, with or without causal association with vaccine usage [1]. They are expected to occur acutely after the administration of an injectable, as is reported in the summary of product characteristics (SmPC) of the mRNA-1273 vaccine [2]. However, there are also some reports of delayed injection-site reactions as AEFIs of mRNA vaccines against SARS-CoV-2 [3-6]. The occurrence of large local reactions may impact adherence to vaccination, particularly to the second dose, compromising the efficacy of the vaccine. Objective/Aim: To describe a case series of 15 patients with delayed large local reactions (dLLR) to the mRNA-1273 vaccine. Methods: We analysed a case series of 15 patients presenting dLLR to the mRNA-1273 vaccine, which were reported to the Porto Pharmacovigilance Centre between May 21 and June 2021 by a physician at a COVID-19 vaccination centre. We analysed: (1) age and sex of the patient; (2) type of AEFIs-Preferred Term (PT) hierarchy level coding, according to the MedDRA (Medical Dictionary for Regulatory Activities); (3) time to onset after immunisation; and (4) therapeutic prescribed. Results: Almost all the cases were observed in women (n = 14). The median age for all patients was 53 years (range 27-73). According to the PT, six types of AEFIs were reported: vaccination site erythema (n = 15), vaccination site warmth (n = 14), extensive swelling of vaccination limb (n = 9), vaccination site pain (n = 2), vaccination site pruritus (n = 1) and vaccination site oedema (n = 1). In ten patients, the reactogenic reaction included three AEFIs: erythema and warmth at the vaccination site with extensive swelling of the limb. The median time to onset was 7 days after the first dose (range 6-14). Seven patients received treatment for their symptoms: antihistamine (n = 7), corticosteroid (n = 3), NSAID (2), cryotherapy (n = 2) and antibiotic (n = 1); for eight patients the treatment remains unknown. Conclusion: We report a series of dLLR after the mRNA-1273 vaccine, which probably represents an AEFI not yet described in the SmPC. The pathophysiological mechanism underlying this dLLR remains unclear, although the clinical criteria for these reactions are consistent with delayed-type hypersensitivity. Further insight on the occurrence of this clinical situation is crucial to