It's a touchy topic right now. Some of you will be reading that word nonchalantly, it's a medical treatment you had as a kid and haven't thought about since.
For many, though, your blood is pumping and your heart rate is increasing as you wonder which side of the fence I'm on, eager to put your finger to the keyboard and smash out an emotional response defending your stance.
Am I a Big Pharma sheep part of a global conspiracy - involving politicians, government organisations, media, hospitals, doctors, and pharmaceutical companies - to poison the world's children?
Or am I a gullible parent who believes I have unearthed a top-secret plan to make everyone sicker and pay for more medical treatment that is being censored by the ominous THEY - despite the information being searchable on the internet?
It's hard not to get emotional about something that involves the health of your children, your family members, your loved ones.
Because no matter what side of the fence you're on, that's what it boils down to.
You either believe vaccines are going to help your children and loved ones fight off dangerous and deadly diseases, or you believe the vaccines are causing more damage than the diseases themselves.
Either way, you believe you're on the right side of history, that the non-believers will be proven wrong in a fiery blaze of glory.
But that's not how it works.
How many studies does it take to prove something is safe for general use?
A study of more than 650,000 children proved vaccines do not cause autism, but that is still not enough to change the minds of doubters.
The anti-vaccination conspiracy is spreading to such an extent that district health boards are saying diseases almost eradicated in New Zealand are being seen again, like the recent outbreaks of measles.
These myths persevere because of human nature - when things go wrong, we want something to blame.
When a parent sees their child display signs of autism, some will, despite all evidence to the contrary, come to the conclusion it was the shots that did it and turn in desperation to conspiracies for an explanation.
The biggest sign of a conspiracy theorist is that when shown evidence contradicting their beliefs, they will not weigh the new information and change their opinion, but instead will double down on their belief, claiming the evidence is false, fabricated or unreliable rather than admit they were wrong.
I don't blame conspiracy theorists for trying to find answers in a confusing world. We're all just trying to find our way in life with the best information we have.
None of us is immune to being sucked into a conspiracy theory if it pushes the right buttons.
Our best protection is to keep our minds open - and to be sceptical of anything and everything we read on the internet.