Parents who refuse to immunise their children are being warned they're putting everyone around them at risk.
A new campaign has been launched to combat a staggering jump in the number of vaccine objectors, by fighting fear with facts.
Thousands of parents still need convincing, but mother of four year old Nicholas Saunders says immunisation was never in question.
"You can't imagine losing a child, so I didn't think twice about it," Sarah Saunders said.
"I know one family who hasn't immunised their children.. and they can't send their kids to daycare."
Thirteen years ago, the number of registered vaccine objectors was a little over 4000. Now there are more than 30,000.
Experts say that these parents aren’t just putting their own kids at risk, they are putting society as a whole at risk.
That's why some of the nation's leading doctors developed a new information booklet.
"There are many irrational fears out there and there are individuals feeding those fears and it really is to the detriment of our young people,” Suzanne Cory from the Australian Academy of Science said.
The Australian Medical Association says it's fighting an online campaign which is putting doubts into parents minds.
While some parents feel strongly against immunising their children, many are afraid to speak publicly about it.
Even the anti-vaccination group won't talk on camera for fear of being misquoted.
For information on where to order the booklet, visit the Australian Academy of Science website.