Proper vaccination is entirely invisible. When people die due to a vaccination not being 100% effective or due to a bad reaction, people claim it's useless. Then more people stop vaccinating, which then hurts herd immunity and makes the vaccine less effective which then causes more people to not take it and start a nasty cycle.
You can't point to the lives vaccines have saved until you have a travesty caused by people not being vaccinated. Unfortunately this cycle will likely make completely eradicating diseases in the future really difficult without compulsory vaccinations.
Everything may as well be invisible if you refuse to look at it. There have been very, very few studies done on the long term effects of vaccines. All the general public knows is that the CDC [1] assures them that they "know there is not a plausible biologic reason to believe vaccines would cause any serious long-term effects." [2]
The widespread belief in the correctness of this almost entirely untested hypothesis is worth tens of billions of dollars per year to private corporations, by the way.
[1]: https://thehill.com/blogs/congress-blog/politics/452654-for-... [2]: https://www.cdc.gov/vaccines/parents/tools/parents-guide/par...
Worse yet, what if your baby can't get the vaccine because they have another disease that precludes getting a vaccine? What if your baby dies because there isn't any more herd immunity?
Two babies dying in 2018 from a wrongly-mixed vaccine is a travesty, but that was a medical mistake. Thousands of babies dying because of ignorance and arrogance is the real sin.