Bell’s palsy (facial nerve palsy)
What: Sudden facial weakness on one side.
Which vaccines: Small signal noted in early mRNA vaccine trials and some surveillance, though causal link uncertain.
How common: Very rare; most cases recover. PMC
Transverse myelitis / other spinal cord inflammation
What: Inflammation of the spinal cord causing weakness, sensory changes.
Which vaccines: Reported as single cases/rare clusters in early surveillance; signal is low and investigations continue.
How common: Extremely rare. Taylor & Francis Online
Arrhythmias and palpitations (non-myocarditis cardiac events)
10. Arrhythmias and palpitations (non-myocarditis cardiac events)
What: Heart rhythm disturbances post-vaccination sometimes reported; many are benign and transient.
Which vaccines: Reported across types in surveillance data.
How common: Uncommon; often self-limited and investigated to rule out myocarditis. PubMed
Multisystem inflammatory syndrome (MIS)-like presentations
What: Hyperinflammatory syndrome (more commonly reported after infection, rare after vaccination).
Which vaccines: Mostly linked to SARS-CoV-2 infection; very rare vaccine-associated reports exist and are investigated.
How common: Extremely rare. PMC
