Left Bell's palsy following the first dose of mRNA-1273 SARS-CoV-2 vaccine: A case report

Abstract

Even though no definitive link has been established, Bell's palsy has been described as a potential side effect of SARS-CoV-2 mRNA vaccines in a few reports, and the US Food and Drug Administration has recommended strict surveillance of its occurrence in the vaccinated general population. We present the case of a previously healthy 35-year-old female patient who developed Bell's palsy 12 h after receiving the first dose of the mRNA-1273 vaccine. Her general practitioner performed the diagnosis, and corticosteroid treatment was initiated, with slow symptoms improvement. The neurologist's evaluation and a contrast-enhanced brain Magnetic Resonance Imaging revealed a subtle enhancement of the left facial nerve, confirming the diagnosis of Bell's palsy.

Keywords: Bell's palsy; COVID-19 vaccine side effects; Facial nerve paralysis; Moderna vaccine; SARS-CoV-2 vaccine.

Fig. 1

CISS (A) (field of view 180 × 180 mm, matrix 256 × 256, voxel size 0.6 × 0.6 × 0.6 mm, TR 5.63 ms, TE 2.48 ms, flip angle 70°) and dark fluid para-axial reconstruction (B) (Field of view 280 × 245 mm, matrix 218 × 256, voxel size 1.1 × 1.1 × 1.0, TR 6000 ms, TE 359 ms) shows the facial and vestibulocochlear nerves entering the internal auditory meatus with regular morphology and thickness (arrows).

Fig. 2

(A) post contrast axial T1-weighted sequence (A) (field of view 250 × 180 mm), matrix 290 × 448, voxel size 0.6 × 0.6 × 0.6 mm, TR 8.16 ms, TE 3.15 ms, flip angle (15°) and reconstruction at 3 mm thickness (B) showing contrast enhancement of the distal intracanalicular and labyrinthine segments of the left VII nerve (arrows).