Covid-19 vaccine: four years later, the list of persistent symptoms is growing

Anaphylaxis / Severe allergic reaction

• What: Rapid onset allergy (hives, breathing difficulties, hypotension).

• Which vaccines: Reported with mRNA and other vaccines but overall extremely rare.

• How common: Rare — vaccination sites monitor recipients for 15–30 minutes and are prepared to treat anaphylaxis immediately.

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.

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.

Arrhythmias and palpitations (non-myocarditis cardiac events)