Published:February 24, 2021
DOI:https://doi.org/10.1016/S1473-3099(21)00076-1
Al Ozonoff, Etsuro Nanishi, Ofer Levy
In light of the ongoing pandemic, development of vaccines to protect against SARS-CoV-2 infection and COVID-19 disease is an important public health priority. As of February 2021, two SARS-CoV-2 vaccines have received emergency use authorisation by the US Food and Drug Administration (FDA), both of which use mRNA technology. While the safety data are reassuring, phase 3 studies of both vaccines demonstrate an imbalance of cases of Bell's palsy in the vaccine groups compared with the placebo groups. This Comment has three purposes: to briefly review the literature on the association of Bell's palsy with vaccination, and vaccination for respiratory viruses such as influenza in particular, to consider biological mechanisms that might explain observed associations, and to reconsider statistical and epidemiological evidence from the reported safety data of the SARS-CoV-2 vaccine trials.
Associations between influenza vaccines and Bell's palsy have been studied extensively (table). Elevated incidence of Bell's palsy among recipients of an inactivated intranasal influenza vaccine was reported in a study conducted in 2000–01.1 Since this vaccine contained the Escherichia coli heat-labile toxin as a mucosal adjuvant, which undergoes retrograde neuronal uptake, it was suspected that heat-labile toxin could affect the seventh cranial nerve through such an interaction. Potential signs of Bell's palsy have been reported following parenteral seasonal influenza vaccinations,2 and influenza H1N1 monovalent pandemic vaccinations.3, 4 However, the association between parenteral influenza vaccines and Bell's palsy was not reproducible in other studies.
https://www.thelancet.com/journals/l...076-1/fulltext
DOI:https://doi.org/10.1016/S1473-3099(21)00076-1
Al Ozonoff, Etsuro Nanishi, Ofer Levy
In light of the ongoing pandemic, development of vaccines to protect against SARS-CoV-2 infection and COVID-19 disease is an important public health priority. As of February 2021, two SARS-CoV-2 vaccines have received emergency use authorisation by the US Food and Drug Administration (FDA), both of which use mRNA technology. While the safety data are reassuring, phase 3 studies of both vaccines demonstrate an imbalance of cases of Bell's palsy in the vaccine groups compared with the placebo groups. This Comment has three purposes: to briefly review the literature on the association of Bell's palsy with vaccination, and vaccination for respiratory viruses such as influenza in particular, to consider biological mechanisms that might explain observed associations, and to reconsider statistical and epidemiological evidence from the reported safety data of the SARS-CoV-2 vaccine trials.
Associations between influenza vaccines and Bell's palsy have been studied extensively (table). Elevated incidence of Bell's palsy among recipients of an inactivated intranasal influenza vaccine was reported in a study conducted in 2000–01.1 Since this vaccine contained the Escherichia coli heat-labile toxin as a mucosal adjuvant, which undergoes retrograde neuronal uptake, it was suspected that heat-labile toxin could affect the seventh cranial nerve through such an interaction. Potential signs of Bell's palsy have been reported following parenteral seasonal influenza vaccinations,2 and influenza H1N1 monovalent pandemic vaccinations.3, 4 However, the association between parenteral influenza vaccines and Bell's palsy was not reproducible in other studies.
https://www.thelancet.com/journals/l...076-1/fulltext
Comment