One of the explanations I have received for the relative dearth of VAERS analysis, despite it being such a rich source, is that it is “unreliable.” Various forms of criticism are levelled.
One favourite is that “VAERS does not establish causality.” This is quite true, in a sense. If a person receives a vaccine, and then has a seizure two days later, it is not clear whether those two events were related. However, the closer in time the two events are, the harder it gets to argue that we are just looking at a coincidence. A seizure fifteen minutes after a vaccine is fairly compelling, I would think.
Another favourite way of diminishing VAERS is that “anyone can report anything to VAERS.” Well, I suppose so. From what I understand about VAERS, a reporting person needs to included their name and contact information, and there is verification of reports by VAERS staff apparently, so I doubt that widescale fraud is a real issue with VAERS.
On a related note is the fact that non-healthcare workers can submit reports. As someone who reads a fair number of VAERS reports, I don’t see this as much of a criticism, in that a poor-quality report (fuzzy on details, timeline that makes no sense) makes itself known without too much difficulty for the reader.
Finally, I have heard VAERS being diminished because of either over-reporting, or under-reporting. From the point of view of looking for “safety signals,” we can put our attention on the over-reporting aspect — under-reporting only means that when we find a “safety signal”there is a good chance it has validity. But regarding over-reporting, I have heard the argument that because the vaccines are new, people are going to report everything.
Maybe, but that should also be the case for other vaccines when they are first introduced. I have not seen any indications of a “novelty over-reporting effect” for the Shingrix Herpes Zoster vaccine, which was introduced in 2017.
VAERS data was employed by the CDC in analysing its myocarditis situation over the summer of 2021. Surely if the data was unreliable, they would not do so.
Although this brings up the insoluble mystery of why the CDC has been so slow to acknowledge the dozens of emerging “safety signals” with covid vaccines…