This is their Disclaimer from your link; Not quite sure how to interpret it. Disclaimer: Please note that VAERS staff follow-up on all serious and other selected adverse event reports to obtain additional medical, laboratory, and/or autopsy records to help understand the concern raised. However, in general coding terms in VAERS do not change based on the information received during the follow-up process. VAERS data should be used with caution as numbers and conditions do not reflect data collected during follow-up. Note that the inclusion of events in VAERS data does not infer causality.