Does the development of Bell's Palsy (Idiopathic Facial Paralysis) following vaccination increase the risk of recurrence with subsequent vaccine administration?

From the Guidelines

Developing Bell's palsy after one vaccine does not significantly increase the risk of it occurring after another vaccine, and the benefits of vaccination generally outweigh the potential risks. Bell's palsy has been reported as a rare adverse event following some vaccinations, particularly COVID-19 vaccines, with an approximate risk of 3-8 cases per 100,000 vaccinations 1. The Pfizer/BioNTech BNT162b2 and Moderna mRNA-1273 COVID-19 vaccines have shown a slight increase in Bell's palsy cases, with 4 cases in the vaccine group compared to 0 or 1 case in the placebo group, respectively 1. However, these cases are still extremely rare and do not necessarily indicate a causal relationship.

Key Considerations

• The mechanism behind vaccine-associated Bell's palsy is not fully understood but may involve an immune-mediated inflammatory response affecting the facial nerve.
• Most cases of Bell's palsy resolve completely within weeks to months, with or without treatment.
• Having one episode of Bell's palsy does not necessarily predispose an individual to another episode following different medical interventions.

Recommendations

• If you've experienced Bell's palsy after a previous vaccination, discuss your specific medical history with your healthcare provider before receiving another vaccine.
• Your healthcare provider may consider factors such as the severity of your previous reaction, the type of vaccine involved, and your overall health status when determining the best course of action.
• In most cases, the benefits of vaccination outweigh the potential risks, even for those with a history of Bell's palsy.

From the Research

Bell's Palsy and Vaccine Association

• The development of Bell's Palsy after a vaccine does not necessarily increase the risk of it happening with another vaccine, but there is evidence to suggest a possible association between vaccine administration and the onset of symptomatic Bell's Palsy 2, 3.
• A case series and nested case-control study found an increased risk of Bell's Palsy after CoronaVac vaccination, with an adjusted odds ratio of 2.385 (95% CI 1.415 to 4.022) 3.
• Another study found that Bell's Palsy is a rare complication that can occur after receiving the COVID-19 vaccine, with the majority of patients being female and aged between 31-40 years 4.
• A systematic review of reported cases of Bell's Palsy following vaccination against COVID-19 found that Pfizer and Moderna vaccines were the most common vaccines among articles that reported the cases of Bell's Palsy, and that left-sided paralysis was more common than right-sided paralysis 5.

Risk of Bell's Palsy after Vaccination

• The age-standardised incidence of clinically confirmed Bell's Palsy was 66.9 cases per 100,000 person-years (95% CI 37.2 to 96.6) following CoronaVac vaccination and 42.8 per 100,000 person-years (19.4 to 66.1) for BNT162b2 vaccination 3.
• The beneficial and protective effects of the inactivated COVID-19 vaccine far outweigh the risk of this generally self-limiting adverse event 3.
• Further studies with larger sample sizes are necessary to assess the association between Bell's Palsy and the dose-response of the COVID-19 vaccine 5.

Treatment and Outcome of Bell's Palsy

• Treatment with valacyclovir and prednisone has been shown to be effective in patients with Bell's Palsy, with a significantly better outcome compared to patients given no medical treatment 6.
• The present study showed a significantly better outcome in patients with Bell's Palsy treated with valacyclovir and prednisone, especially among elderly patients 6.