Kort efter vaccination kan der opstå en akut overfølsomheds- lignende reaktion resulterende i lettere neurologiske symptomer, som kramper og/ eller ekscitation, som normalt aftager efter nogle minutter uden at kræve behandling.
Immediate systemic hypersensitivity-like reactions may occur after vaccination, resulting in minor neurological symptoms such as tremors and/ or excitation, which normally resolve within minutes without requiring treatment.