All the people who bring cases to the vaccine court, all they're required to do is present a theory connecting the vaccine to the consequence, show an appropriate, an approximate timeline that links the two, and show that there's not another plausible biological reason the injury or death happened. It's a very low standard of proof, and it's intentionally that way because they want to support the people who experience any possible side effects without forcing them to actually prove any scientific causation, which they could never do.