Of course, no anti-vaxer I’ve met argues that vaccines are always unsafe, or are never effective.
So their argument is implicitly one of degree.
• What they’re really arguing is that vaccines aren’t worth the risk.
• They’re unsafe too much of the time, or the consequences too severe, such that this outweighs any possible effectiveness they might have in preventing diseases.
“Would it be possible for any information (actual or hypothetical) to change their minds?”
In other words, is any level of risk or failure to prevent diseases acceptable to them, or must vaccines have absolutely no side effects and be 100% effective in preventing the conditions they’re used for?
Assume for the sake of this thought experiment that the data could be collected by any authority they consider credible, but it must use the scientific method and statistically significant samples. (No “my sister’s cousin’s best friend said...”)
I would venture to guess that anti-vaxers engage in riskier, more life-threatening, less effective, and completely unnecessary behavior all the time.
I’m guessing many of them let their children:
• Ride in cars
• Consume sugar
• Walk to the park
If posed with these arguments, they’d explain that these activities are worth the small risks they carry. Their kids get benefits from riding in cars, ingesting moderate amounts of sugar, walking to the park, or swimming in pools.
So they’ve shown to be willing to accept life-threatening risks when offset by sufficient benefit.
Now they must show that vaccines are more risky than these things or provide such negligible benefit that it’s just not worth it.
This is hard.
Overwhelming statistically significant data shows vaccines to carry extremely minimal (and usually not severe) side effects. It also shows them to be highly effective. (Again, not perfectly so, but nobody’s claiming otherwise).
What number of people studied would you consider enough to feel sufficiently convinced of vaccines safety and effectiveness, since you feel the existing data is insufficient at best and damning at worst?
• More people studied than the hundreds of thousands who already have been?
• Zero side effects?
• Complete effectiveness 100% of the time?