The proof is indisputable, vaccines work.

The temptation, when taking up the subject of vaccinations, is to go for brevity. Rather than use approximately 400 words to describe this public health marvel, the simple statement ‘Vaccinations work’ suffices.
Or, to steal the motto from a clever T-shirt:
Vaccines cause adults.
But the public health consequences are too important and grave for mere pithiness. The unfortunate fact is that the anti-vaccine movement is nearly as old as vaccines themselves, dating to in 1763, according to the Measles and Rubella Initiative. Something about receiving a shot to prevent a disease — rather than cure it — hits a nerve in many people.
The modern anti-vaccine movement dates to the late 1990s, and the work of a now-discredited scientist. Parents began to question whether autism diagnoses or other childhood health problems were connected to vaccines.
The fact is, vaccines are an incredible achievement of civilization. We have all but eradicated smallpox, polio and other potentially fatal diseases. While side effects have occurred, they are incredibly rare.
But the resistance to vaccinations among parents has persisted. And children have suffered. According to the Measles and Rubella Initiative, there were no cases of measles transmitted by U.S. patients in 2000. But by 2013 the disease had returned.
According to The Centers for Disease Control and Prevention, 228 individual measles cases have been reported this year. The whole of 2018 saw 372 cases. Clearly, many children across the United States are no longer receiving the vaccines that would protect their health and the health of those around them. This has led to popular outrage and efforts in some cases to limit the ability of parents to exempt their children from vaccinations.
Kansas allows parents to opt out of school immunization requirements for religious reasons. Most states allow similar exemptions, but if childhood diseases roar back across the country, we should together as a society decide how to protect children.
Vaccines are safe and effective and widely available. And the more people vaccinated, the safer we all are. “Herd immunity” refers to the concept of enough individuals being resistant to a disease that it no longer spreads through a community, even to newborn children who aren’t able to be vaccinated yet.
Ultimately, the advice of doctors and our triumph over a host of illnesses should be all the proof needed that vaccines work.