Alberta's deputy chief medical officer of health is raising concerns about dropping immunization rates in the province over the last five years.
The numbers are so low for some diseases, such as whooping cough, that so-called "herd immunity" is affected — meaning not enough people are being vaccinated to stop the spread.
Experts are watching measles closely too.
"I'm very concerned," said Dr. Martin Lavoie.
"We are going to probably see a higher number of cases of those diseases if the rates continue to go down."
More parents opting out
Lavoie says people need to know diseases like polio are still a threat.
"People were paralyzed and [had to use] iron lungs, and they have permanent damage," he said.
Health officials are planning a survey to find out just what Albertans think about immunization.
Sarah Webb is one of a growing number of parents who are delaying or avoiding immunization altogether.
"When I was young I stopped breathing when I received my first vaccination," she said as she placed her one-year-old daughter on a red slide at a local indoor playground.
"So I was worried she might have a similar reaction, so we've held off."