Analytical review of facial nerve palsy following SARS-CoV-2 vaccination: comprehensive assessment

Purpose: The SARS-CoV-2 vaccination has reduced COVID-19 infection, though facial nerve palsy (FNP) has emerged as a notable side effect of the vaccine. We evaluated the current literature on the clinical presentation and outcomes of FNP related to COVID-19 vaccination.

Methods: A comprehensive search of seven databases was conducted for studies up to January 2023. We included individually reported patients on FNP following COVID-19 vaccination, while cases with co-existing neurological disorders or secondary causes of FNP were excluded. Pooled descriptive and inferential analyses were conducted, with prognostic factors evaluated through regression and Kaplan-Meier survival analysis.

Results: A total of 33 studies were included, with data from 52 patients who developed post-COVID-19 vaccination FNP (PV-FNP). Most cases (71%) followed mRNA vaccines, primarily occurring after the first dose and within the first week post-vaccination. Nearly all cases (98%) were unilateral, with Grade III palsy being most common. Complete recovery was achieved in 55% of patients, significantly lower than pre-pandemic rate (83%). A longer latency period was associated with a reduced likelihood of full recovery, and females experienced faster recovery compared to males.

Conclusion: FNP following SARS-CoV-2 vaccination tends to present as mild and unilateral, with a lower full recovery rate compared to pre-pandemic cases. Symptoms often develop within the first week after vaccination, and earlier symptom onset is associated with a higher likelihood of full recovery. Recognizing these patterns provides valuable guidance for clinicians in counseling patients about prognosis and managing follow-up care effectively.