Important: VAERS reports alone cannot determine if a vaccine caused an adverse event. Reports may contain incomplete, inaccurate, or unverified information. Correlation does not equal causation.
Investigation appears in 2,586 VAERS reports across all vaccines. Of these, 41 reports also mentioned death and 613 involved hospitalization. The severity rate (deaths + hospitalizations as a percentage of reports) is 25.3%. The top vaccines associated with this symptom are COVID-19, Unknown Vaccine, Flu (Seasonal). Remember: VAERS reports show temporal association, not causation.
Investigation has been reported 2,586 times in VAERS from 1990 to 2026.
Of these reports, 41 were associated with death (1.59%) and 613 involved hospitalization.
The overall serious outcome rate (death or hospitalization) for reports mentioning Investigation is 25.3%.
This data comes from the Vaccine Adverse Event Reporting System (VAERS), jointly managed by CDC and FDA.