Bell's Palsy After 24 Hours of mRNA-1273 SARS-CoV-2 Vaccine

Coronavirus disease 2019 (COVID-19) has become the fastest-spreading pandemic of the 21st century. Various vaccines have been made available via emergency use authorization. Currently, two mRNA vaccines are being offered internationally, BNT162b2 and mRNA-1273. In randomized trials of these vaccines, the incidence of Bell's palsy in the vaccinated group does not statistically exceed the placebo group. The FDA recommends increased surveillance for Bell's palsy as a potential side effect with the administration of the vaccines among larger populations globally. There have been a few case reports of Bell's palsy associated with mRNA vaccines. Type I interferons have been proposed as the potential mechanism linking mRNA COVID-19 vaccines to Bell's palsy. Here, we report the case of a 36-year-old previously healthy patient who developed symptoms of Bell's palsy along with left-arm numbness, tingling, and subjective weakness masquerading as a subacute stroke after receiving the second dose of the mRNA-1273 vaccine. CT and MRI of the brain were unremarkable. He was discharged home with a diagnosis of Bell's palsy and improved on follow-up. mRNA COVID-19 vaccines may be considered a risk factor for Bell's palsy.