Has Coranavirus Disease 2019 Changed the Incidence and Outcome of Bell's Palsy?

Objectives: (1) To determine whether the incidence of Bell's Palsy (BP) increased during the pandemic. (2) To investigate whether the outcomes of patients with BP and COVID-19 infection or vaccination differ from those in the pre-pandemic era.

Patients with BP were studied in 2 periods retrospectively (March 2021-March 2022 and August 2018-August 2019). A prospective study from March 2021 to March 2022 was also performed. Primary outcome was grade ≤Ⅱ in the House-Brackmann (HB) and/or >70 in the Sunnybrook facial grading system (SFGS) scales at the 12-week visit. Reverse transcriptase polymerase chain reaction (PCR) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and enzyme-linked immunosorbent assay-based SARS-CoV-2 immuonoglobulin G (IgG) test (blood) were measured.

About 162 and 196 patients with BP were identified between March 2021 and March 2022 and August 2018 and August 2019, respectively. Forty-seven patients (29%) entered the prospective study; 85% had HB grades I or II, while 92% had an SFGS score of 71-100 at the last visit. Only 3 patients (6.5%) had a positive PCR during the initial episode, whereas 35 patients (77%) had positive IgG SARS-CoV-2. There was no association between positive PCR and facial function outcomes. Of the 162 patients, 105 (67%) had received COVID-19 vaccine. In 23 of them (22%), the paralysis appeared within the first 30 days after a vaccine dose.

Coronavirus disease 2019 did not increase the incidence of BP. A direct association between the coronavirus and BP outcome cannot be established. The considerable number of patients developing BP within the first month suggests a possible association between COVID-19 vaccines and BP.