Are all adverse events reported to VAERS caused by vaccines? (FAQより)
No. Some adverse events might be caused by vaccination and others might be coincidental and not related to vaccination. Just because an adverse event happened after a person received a vaccine does not mean the vaccine caused the adverse event.
VAERS accepts reports of adverse events following vaccination without judging the cause or seriousness of the event. VAERS is not designed to determine if a vaccine caused an adverse event, but it is good at detecting unusual or unexpected patterns of reporting that might indicate possible safety problems that need a closer look.