A man experienced two discrete contralateral facial palsies, one after each dose of the Pfizer-BioNTech vaccine.

The first episode developed 5 hours after the 61-year-old man received the first dose of the vaccine, reported Abigail Burrows, MBBS, of Royal Surrey County Hospital NHS Foundation Trust in Guildford, England, and colleagues.

The second occurred 2 days after he received the second dose and was more severe, they wrote in BMJ Case Reports. On both occasions, the patient was diagnosed with Bell’s palsy.

“Our case is the first reported incidence of unilateral facial nerve palsy occurring after each dose of the Pfizer-BioNTech vaccine,” Burrows said.

“Although a causal relationship cannot be established, healthcare workers should continue to report these findings so that we can investigate any potential links,” Burrows told MedPage Today. “Given the rapid rollout of the COVID-19 vaccine, it is important to share and report on adverse effects so that we are more aware and better informed as clinicians.”

Facial paralysis can occur after viral infections, traumatic injury, cancer, or during pregnancy. Bell’s palsy, the most common cause of facial paralysis, is a form of temporary paralysis or weakness on one side of the face that stems from dysfunction of cranial nerve VII (facial nerve). Symptoms appear suddenly over a few days and generally start to improve after a few weeks.

During the phase III Pfizer-BioNTech and Moderna COVID-19 trials, seven cases of facial paralysis or Bell’s palsy were reported in the vaccine groups (seven of 35,654), and one case was seen in the placebo groups (1 of 35,611). A causal relationship was not established, but the FDA recommended that vaccine recipients be monitored.

Since then, other studies have reported on rare cases of Bell’s palsy occurring after vaccination. To date, these all have involved single episodes of unilateral facial nerve palsies.

In their case report, Burrows and colleagues described a Caucasian man with no previous history of facial nerve palsy. He had high BMI, hypertension, hypercholesterolemia, and insulin-dependent type 2 diabetes. Both vaccine doses were administered in his left arm.

The patient initially developed right-sided facial weakness 5 hours after the first dose of the Pfizer-BioNTech vaccine on Jan. 18, 2021 and presented to the local emergency department (ED) the next day. On exam, he had a right-sided lower motor neuron facial palsy with incomplete eye closure and no forehead movement. Blood tests were unremarkable and CT head scan showed no acute pathology.

The patient was discharged with a 60-mg dose of prednisolone and a weaning dose over a 4-week period. The right-sided facial nerve palsy resolved completely. The patient scheduled his second vaccine shot, which he received 6 weeks after his first dose.

Two days after the second shot, the man developed a more severe left-sided facial nerve palsy. He visited the ED again and received a 7-day course of 60-mg prednisolone.

After 1 week of steroid treatment, the patient reported dribbling and dysphagia symptoms. On exam, he had a severe left-sided facial nerve palsy of House Brackmann grade 4 with incomplete left eye closure and a Sunnybrook Facial Grading System score of 13. The House Brackmann scale describes facial nerve paralysis severity (grade 1 is normal and grade 6 represents total paralysis). The Sunnybrook Facial Grading System incorporates resting symmetry, synkinesis, and symmetry of voluntary movement.

The rest of his neurologic exam and gait were normal. The patient continued on steroids for another week. Two weeks later, he reported his symptoms had greatly improved and had almost returned to normal.

This case described the earliest onset of symptoms from timing of administration of the vaccine, Burrows and colleagues noted.

“The occurrence of the episodes immediately after each vaccine dose strongly suggests that the Bell’s palsy was attributed to the Pfizer-BioNTech vaccine, although a causal relationship cannot be established,” the researchers wrote.

The patient has been advised to discuss future mRNA vaccines with his physician on a case-by-case basis, considering risks and benefits of each vaccine, they added.