For those interested in ways the gubmint tries to track reports of vaccine reactogenicity, and/or adverse events...
The companies with EUA or licensed (aka "approved) vaccine, there are extensive ongoing regulatory requirements in the CFR, and FDA monitors compliance. This is true for medical devices and equipment as well.
There are other parallel programs for information gathering and mining. For example, for vaccines, CDC/FDA have a had a special program for several decades:
CDC VAERS
About VAERS:
https://wonder.cdc.gov/wonder/help/vaers.html#
Remember: VAERS data collection is "wide open." I imagine that there may be some cybersecurity tools in place, but basically it looks like anyone can report anything.
The procedures, methods, tools, forms, instructions, et cetera used by manufacturers as they collect data to support EUA and likely later approval, are almost certainly far more rigorous than a "wide open" tool like VAERS. May be important for some folks to understand that.
It can be helpful to consider the VAERS disclaimer on this page:
https://wonder.cdc.gov/VAERS.html
Here is a video on generating VAERS reports:
https://www.youtube.com/watch?v=cOH7cFWS7o4&t=637s