Meningococcal vaccine might raise risk of Bell’s palsy
In a study of almost 48,900 vaccinated individuals, investigators observed a temporal association between development of Bell’s palsy and administration of quadrivalent meningococcal conjugate vaccine (MCV4) that protects against serogroups A,C, Y, and W (MenACWY) when the vaccine was given at the same time as other vaccines. Whether this association was because of chance, concomitant vaccination, or an underlying medical history predisposing to Bell’s palsy was not clear, however.
Study participants, who were aged 11 through 21 years, received their first dose of MenACWY as part of routine clinical care at 1 of 3 centers of Kaiser Permanente Southern California. Investigators then followed these patients for a year after vaccination via electronic health records to track development of 26 prespecified “events of interest” (EOIs) related to neurologic, rheumatologic, hematologic, endocrine, renal, and pediatric conditions. Researchers defined specific risk windows—time periods in which they hypothesized that the risk of events might be affected by vaccination—for each EOI, based on previous published literature. They defined the comparison window as from the end of the risk period up to 1 year after vaccination.
About 72% of participants received 1 or more vaccines along with their first or booster MenACWY vaccinations, most often human papillomavirus (HPV), tetanus toxoid, reduced diphtheria toxoid, acellular pertussis, adsorbed (Tdap), and influenza. About 18% received 1 or more other vaccines in the 6 months before their index MenACWY vaccine, usually influenza but often Tdap or HPV.
Of a total of 1127 instances of EOIs during the 1-year observation period, 260 arose in the risk window and 867 in the comparison window. Asthma was the most common EOI (n=841) followed by seizure (n=81). Only 14 patients experienced an episode of more than 1 EOI during the observation period. Analysis showed that of these EOIs, MenACWY vaccination was associated with a statistically significant increased risk only of Bell’s palsy, with 8 cases in the risk window and 10 in the comparison window. Among those 8 in the risk window, 6 received 1 or more vaccines concurrently with MenACWY and 2 did not.
Indeed, further analysis showed an increased risk for Bell’s palsy only in individuals receiving concomitant vaccines with no increased risk for those who received the meningococcal vaccine alone. Further, 3 of the 8 patients who developed Bell’s palsy in the risk window had comorbidities and infections that could be a prelude to the condition. All 8 cases resolved completely (Tseng HF, et al. Pediatrics. 2017;139:e20162084).
These findings do not mean that you should avoid use of this vaccine. Of the 26 theorized complications of MenACWY, only 1—Bell’s palsy—was found to be increased after the vaccine, all of the cases resolved, and incidence increased exclusively in patients who received multiple vaccines on the same day. So, continue vaccinating for meningococcus, be ready to reassure savvy parents who have read about this complication, and, perhaps, consider giving MenACWY as a single vaccine. —Michael G Burke, MD