Association of COVID-19 vaccination and Bell’s palsy in a Philippine tertiary hospital

Background: Bell’s palsy or peripheral facial palsy after coronavirus-19 (COVID-19) vaccination is relatively rare and presents only as an adverse event that resolves spontaneously. The increasing reports of Bell’s palsy after immunization shows an increased risk and this hinders some individuals from acquiring vaccination in this certain time of pandemic.
Methods: This case-control study was performed from September 2021 to March 2022, at the emergency and outpatient departments of a tertiary hospital in the Philippines to determine the association of COVID-19 vaccination and Bell’s palsy. Patients diagnosed with facial nerve palsy were matched by age, sex, and date of consult with control patients admitted for other reasons. The proportion of patients with Bell’s palsy after vaccination was compared between groups, and odds ratio for exposure to the vaccine was calculated. A secondary comparison with the overall number of patients with facial nerve palsy in preceding years was also performed.
Results: Thirty-one patients were evaluated for new-onset facial nerve palsy during the study period. The mean (SD) patient age was 42.9 (15.6) years, wherein 12 (37.8%) were males and 19 (61.3%) were females. Out of the 31 patients, 8 (25.8%) had hypertension, 3 (9.7%) had diabetes mellitus, 1 (3.2%) had dyslipidemia and 2 (6.5%) had previous episode of peripheral nerve palsy. Of the vaccinated cases, 5 (62.5%) received Sinovac, 2 (25%) received the Pfizer-BioNTech vaccine and 1 (12.5%) had Moderna. Comparing recently vaccinated (8 of 31 [25.8%]) with unvaccinated (23 of 31 [74.2%]) patients showed no meaningful difference in age (mean [SD], 46.5 [11.7] vs 40 [16.6] years; P = 0.92), or sex (5 [62.5%] male, 3 [37.5] female) vs 7 [30.4%] male, 16 [69.6] female; P =0.10). The mean (SD) time from vaccination was 6.1 (4.5 [range, 1-14]) days. The calculated OR for exposure to the vaccine among cases was 0.91 (95% CI, 0.40-1.99; P = 0.76). Furthermore, a relatively stable trend of cases of Bell’s palsy was seen during the same period in the preceding years (mean [SD], 27.5 [3.4] cases; median, 28 [range, 23-29] cases).
Conclusion: This study revealed no significant association between new-onset Bell’s palsy and recent vaccination with COVID-19 vaccines. However, it is important to note that Bell’s palsy can be an adverse effect of COVID-19 immunization and is a typically benign condition with excellent prognosis. The protective effects of COVID-19 vaccination outweigh the risk of this generally self- limiting treatable adverse effect.